I normally don’t write long reviews, but thought due to our interesting networking environment, this review may be helpful for others contemplating this Asus AC88U router in more complex situations.

The short summary is that this router has been very capable and refined out of the box (contrary to what some professional reviewers have claimed as “beta” with some Asus routers and users), with only the slightest of “glitches” that should be remedied as the firmware matures. It was a sufficient enough improvement in a very busy mixed network to replace our old workhorse AC68U. For those with the most active networks, the AC88U is probably the current SOTA and should squeeze every last ounce of performance from it.

We have what is best described as a mixed-protocol, mixed-device, high-activity, network. Much of it is wired gigabit ethernet, but with a heavy supporting load of wireless 2.4 and 5 ghz clients, from legacy G to the latest AC Wi-Fi devices. Our broader network has three laser printers/MFPs (including color models), a Mac running OS X server with outboard RAID stack serving 10+TB of local data, three other Mac clients, three PC laptops, two PC workstations, a LAG-ethernet connected NAS unit for all local backups, six Squeezeboxes (wired and wireless) served by LMS locally, five Apple TVs, two network-managed cable boxes, several other smart TVs, Android tablets and streaming clients (Amazon Fire and Roku), two networked BD players, no less than seven iOS devices running both N and AC Wi-Fi, two gaming consoles, a fully populated Cisco 24-port managed switch with multiple LAG connections, and about 2,500 total feet of gigabit ethernet cable to manage. And a fairly active 2.4 ghz guest network on top of all of it for the regular in-law and neighbor visitors and all their devices. The longest Wi-Fi run is about 65 ft through 5-6 walls and across four levels (I do not believe in local repeaters or APs for security reasons). We run our 175/12 ISP WAN pretty much at its limit, with monthly activity typically in the 300-400+ GB range. At any given time, there are never less than 26-28 active clients on our network. Most activity is multiple-client, higher bitrate HD video and audio streaming, and regular larger data transfers, including multiple TimeMachine, local and off-site server backup routines. With all local data, HD video and audio traffic, Internet and cloud video streaming and data transfers, several RDC clients running, and continuous off-site server backups, our network is typically managing and moving hundreds of GB daily across many streams simultaneously. This is a heavy load for any router.

We were among the first buyers of the AC68U as a result. It has been a stable device since day one, with incremental improvements as Asus has refined its firmware. To date, our old AC68U still does a capable job. It is good-looking, petite, and draws no attention to itself. It just does the job. Consequently, I would continue to recommend this now classic AC router for any but the most intense network environments. Where the 68U can now falter for us is on longer and fringe wireless AC and other 5ghz connections during heavier network activity, where speeds and latency can start to fall off. As a result, we started shifting some devices to the 2.4 ghz band to relieve the AC68U. Under peak network activity, some ethernet transfers would also experience a slight drop off (from 100-105 MB/s to perhaps 75-80).

Enter the AC88U. It has several features that helped wring some additional capacity and headroom out of our busy network. The LAG feature is a legitimate IEEE 802.3ad setup, and allows a 2GB pipeline from our server to both Wi-Fi and Ethernet clients. Previously, a LAG connection was confined to Ethernet-side only. The AC88U’s more robust 5 ghz hardware delivers stronger and more stable fringe connections than the 68U, and with more headroom. We can move all our clients back over to 5 ghz with no speed drop off. The AC88U can support multiple HD video streams on all of them simultaneously without any compromises. Fringe 5 ghz devices previously connecting to the 68U at 125-150 mb are now rock solid at 350-400+ mb. Older 5 ghz clients such as the Intel 6300 AGN series are now holding stable connections at or just under 300 Mbps across much longer distances.

Updating the 88U to the latest firmware was an easy affair, taking under 3 minutes. Migration from the 68U to the 88U was fairly painless, with a settings save and upload between them transferring about 80% of our router settings over to the new router. However, some settings need to be manually re-entered, and all settings should be double-checked. I imagine similar later model Asus routers will have a similar experience.

Based on our testing, the AC88U’s more robust processing and transmitting power has improved all network transfer speeds over the 68U by approximately 10-15%, including for WAN traffic. This may not prove significant over a smaller network and/or with smaller data transfers, but for larger volume data transfers and heavy users with lots of clients, it adds up to a faster, more responsive network experience. As with all these matters, YMMV, and I suspect the 68U to be the the full equal of the 88U in less hectic environments. But the biggest gains for us with the 88U were seen with wireless clients, and in the 5 ghz band, particularly over distance.

The 88U is not without its flaws. It is a large and somewhat garish-looking device (we're older and best described as "mature", but I'm sure anyone under 30 will love it), and requires more real estate and electricity than the trim and classy looking 68U did. Its firmware, while surprisingly polished so early, is not yet mature. Most notably, we occasionally experience some very brief page load delays under Safari (2-3 sec), and very infrequently a slight delay when first connecting to our NAS - but once connected, it flies. I would characterize these more as “glitches” than full blown bugs, and expect that they will resolve over the next couple of firmware revisions. However, the entire Apple ecosystem in our house runs flawlessly under it, with all that implies (Airplay, Airdrop, Home Sharing, TimeMachine, FaceTime, etc), and the PCs, Apples and Androids all get along together nicely. The 88U is also eye-watering expensive, and you are paying to be on the bleeding-edge with it. MU-MIMO is an infant technology, and like most consumers, we are not yet using it. Perhaps later. I’m not a lamp-watcher, but the single LED to indicate all switch activity may bother some.

However, the bottom line is the AC88U is probably the strongest, most powerful home/prosumer router currently available. But its advantages over a more mainstream AC router such as the 68U are likely only going to make economic sense in busier, more complex networking environments. I consider it the top choice in any mixed environment, where ethernet is significantly deployed. The only possible current upgrade over the 88U is the tri-band AC5300, which can support even more 5 ghz clients than we have, and makes more sense in a Wi-Fi dominant environment. But for up to 12-15 5 ghz clients, the 88U is its equal. We expect the 88U to be with us for the next 3-5 years before our technology overtakes it, much as the 68U was. Again, for most homes, the difference between the 68U and 88U is not going to justify the price difference. Unless your 68U is starting to strain or stumble, there is little to be gained with the 88U.

I won’t go into all the other features of the AC88U which are common to all Asus routers, such as AiProtection, etc., except to say they are all work well on the AC88U. Having used many router brands over many years, we continue to prefer Asus for its combination of solid, reliable hardware and relatively useful and stable native firmware, and have not found the need for 3rd-party firmware solutions as with some other brands. The Asus Router App needs some work however, and is currently best avoided.

For a little less money, the AC3100 is just about the same router as the 88U, with 4 less ethernet jacks. However, we appreciate the extra ethernet jacks on the 88U to relieve our big switch from supporting server room devices such as printers and our RAID stack.

Should the operation of the 88U change in future, we’ll update our review accordingly. But after about a week with the 88U, we are confident enough to sadly say goodbye to our trusty 68U (which is still worth about $95 on trade-in).

Amazing router, even though it's expensive. I replaced my RTN66U "Dark Knight" router with a Netgear nighthawk, and was thoroughly unimpressed. It had broadcast issues, and performed poorly on NetSpot testing in a relatively small home.
THIS router has two 5Ghz bands, so the coverage issue I experienced with the Netgear were immediately solved. The 5Ghz coverage is as good as the 2.4Ghz band because of this. Now, I can attach more devices to the 5Ghz band, and free up bandwidth on the 2.4 band.
I prefer the Asus UI to Netgear's. It has a more intuitive look and feel to me, and it seems more powerful as well for the users who are more experienced and knowledgeable in setting up home networking.

I've attached wireless speedtests from my router through google fiber. Tests were done about 15 feet from the router.

********4 month update********
Added a photo from pulling a file from my NAS to my laptop. Speeds average 7MB/s when reading. NAS is connected via powerline ethernet adaptors, computer was wireless.
For anyone complaining that this router can't handle gigabit speeds, see my "connected" speedtest. This was done connected to the router via cat5 ethernet cable into my Dell XPS 13 with a USB3.0 ethernet adapter. Note that in the screenshot I included the systray to show the laptop being in airplane mode. I have Google Fiber, and the reason the download isn't FASTER, is because I also have their TV service. The TV leeches bandwidth from your connection, to the tune of about 250-300Mbps because of the lower compression google uses to deliver higher quality television broadcasts. However as you can see on the upload portion, it handled gigabit speeds easily.

I also do a TON of media streaming in my home. This is primarily why I bought this router. I have tried and succeeded streaming up to three 1080p movies from my Synology NAS to my Roku 3, Roku 2, and PS3 which are all connected wirelessly.

It's my opinion that anyone complaining this doesn't do gigabit speeds needs to check their own hardware/connection out, and not blame this router as it CLEARLY will do all it says it will.

-----edit 2/11/2017--------
Added a screenshot of iPerf results. The first set is of 1 laptop to another with one on the 2.4ghz band, the server on the 5ghz band. The second is both laptops on the 5ghz band. I didn't shut anything down on my network to perform these tests, and both "server" and client were wireless.