I am a M-65 junkie / collector. I currently own 5 of these jackets. Over the years I have owed over 15. Some have been knock-offs, some have been genuine government issue. Some of the brands I've had include Golden, John Owenby, So Sew, Alpha, Rolane, Propper, and Rothco/Ultra Force ("Rothco").

Golden, John Owenby, So Sew, Rolane, etc. are genuine GI issue. You will only find them at surplus or vintage stores*. As such, this review is only of the jackets that you will have a decent chance of actually finding. Those brands are Rothco, Propper, and Alpha.

Rothco/Ultra Force
These are the easiest to come across. Almost every army/navy retail and eStore stocks this brand. They come in two versions. First, is the 100% cotton "Vintage" version. Second, is the cotton/poly "Deluxe" version. The Deluxe version comes with a removable liner for colder weather, the Vintage version does not. Neither version is made to military specifications (they ARE knock-offs, after all). The Vintage model is your best option if you are going for, well, the "vintage look." If you are just going for "looks" then this is THE jacket you want. They come pre-faded (and quite nicely, at that), and have a good fabric texture that you won't see in ANY of the other jackets, even the higher-end versions. Next to my 1973 USAF genuine GI issue M-65 jacket, my "vintage" Rothco is my first choice for "looks." However, the Rothco Vintage jacket comes with this corny velcro "Ultra Force" nameplate. You should ditch that. Quickly.

However, there are some downfalls to the Vintage jacket. First, is that since it is 100% cotton, when it gets wet, it gets REALLY wet. Can you say "sponge?" The more expensive versions are treated with some kind of water repellent, and are also made of a nylon/poly blend which keeps you dryer. The Vintage version of the M-65 is NOT, repeat NOT, a jacket you want to wear in rain, snow, sleet, etc for any extended period of time.
Second, the stitching is not as strong as the higher-end jackets. Hence, it will fall apart sooner, but they are still decent quality. I would not be too worried about this issue.
Last, this is not a super warm jacket. It does not come with a liner, so if your going out in really cold weather you need to wear more layers, or buy a liner for it.

The Deluxe version doesn't look as "cool" as the Vintage version, but it is a much better jacket for keeping you warm and dry. It is made of a poly blend (i.e. won't soak-up water like the cotton Vintage version), and it comes with a removable liner. The Deluxe version is a knock-off of the higher-end jackets. It is a decent choice if you want a more functional M-65 than the Vintage version, but don't want to drop the money on the higher-end models. However, Propper might be a better option if you are going the budget route (see below).

ROTHCO BOTTOM LINE: Vintage version is most stylish of all the commercially available M-65 jackets. But, it is a bit thin for really cold weather, and horrible in the rain/snow. The Deluxe version will keep you dry and warm, but if your going cost effective get a Propper (see below).

PROPPER & ALPHA
Both of these are almost identical to each other. Both are as close to military specification as you can find in the commercial market. If you compare these two to the Rothco/Ultra Force jackets you will be able to tell the difference immediately. Both Alpha and Propper have the unhemmed inside "liner" like real GI issue. Rothco does not. Both Alpha and Propper have the very thin hood, which Rothco has beefed up a bit. The hood is not really meant to keep your head dry; it is meant to provide head camouflage. Alpha and Propper have placed the velcro patch of the sleeve extension in the same place as GI issue. Rothco has moved it a bit. I believe that most Propper jackets come with a removable liner, which Alpha does not (sold separately). So Propper wins on that one. What I like better about Alpha is that material and stitching just seems to be of better quality. But even better, the Alpha comes with two internal pockets. None of the other M-65 have internal pockets. Not even GI issue, and I think it is a great improvement over the real version. The Alpha M-65 is a durable, well-built jacket that will last a long, long, long time. If you are considering a M-65 jacket, and just want the "cool looks," get the Rothco Vintage version mentioned above. If you are considering an M-65 for more than just "looks," you really, really, really, owe it to yourself to save up a bit more and go with the Alpha. IMHO, it really is the best of all options. You get what you pay for. Oh, Alpha also has a subsidiary called Knox Armory. They also make M-65 jackets, but I have never seen one. They come stock with a liner. From what Alpha reps have told me, the Knox Armory jackets are more of a "street fit" (what ever that means), and are not quite as good of quality as the Alpha.

ALPHA/ PROPPER BOTTOM LINE: Alpha rocks the M-65 party.

VERY BOTTOM LINE:
Rothco/Ultra Force: Wins for best looks.
Alpha: Wins for best quality.
Propper: Wins for best value to quality balance.

SIZING
M-65 jackets are WAY oversized according to their listed measurements. These jackets were designed to fit over a bulky military uniform, which most of us aren't wearing. I am 5'10, 157 lbs, and have a measured 41 inch chest. Rothco claim that a size medium jacket fits someone with a chest of 37" - 41". Well, guess what size Rothco jacket I own? It is not a medium. It is not even a small. It is an EXTRA SMALL. That is right, an XS. I can even fit a zip-up hoodie underneath it. It is a touch snug with hoodie under it, so you may want to just drop down one size when you order a Rothco jacket. That said, you should REALLY consider dropping down TWO sizes. If you can try these things on before you buy them, do so. You'll be shocked at how over-sized they are. My Alpha jacket is a Small Regular, and it also a bit baggy on me. Again, Alpha claims I should be wearing a medium, but that was HUGE on me. Note, I have never worn an Alpha XS jacket. Who knows, that might even fit me better than my Small Regular. So basic rule with ANY M-65 jacket is drop down AT LEAST one size for a decent fit, and possibly even two sizes.

*vintage trends dot com is a great store for real GI issue vintage military clothes. I am not affiliated with that site any manner what so ever. I am just plugging them as consumer.