I purchased to pair with the DIR-655 router and the DAP-1522 bridge (the bridge isn't really necessary unless you want your wireless network to include non-N band devices). Of the three, this is the only device that I set up that didn't lead to murderous rage. It works great in Medialounge mode (if you want to stream files from multiple computers, set up something like Tversity to act as a media server - this device will detect it) and with Vista Media Center. One caveat - in order to get live tv to record properly, I had to update drivers for my tv tuner. If you get a video error message, you probably have a codec conflict with MCE - uninstall codec packs and video-related software until the problem is fixed - may need to restart computer to notice a change).
In MCE mode, you can access Netflix watch now and download Netflix movies by using the VMC plug-in. Works great.
In medialounge mode, I was able to get the device to play .vob files by using DVDshrink to copy a dvd. I wanted to stream directly from an optical drive, but it's not quite able to do it. It will detect the files and try to play them, but I've only been able to get a couple video frames and a little audio.
The only problem is that I needed to update the firmware. At the time I was using a wireless connection (not sure if the same problem would have occurred if connected via Ethernet), and it wouldn't connect to the internet and check for firmware. I had to download the firmware on my PC, transfer it to a usb device, and connect the usb device to the DSM-750. Note - you will need to unpack the downloaded file, and all files need to be included on the usb, not just the firmware file. After plugging in the usb device, I went to medialounge mode. Don't go to the usb selection. Go to settings, and the device will automatically detect the new firmware and prompt you to install. I believe the folder with the firmware files may need to be on the root of the usb. After updating the firmware, the connection problem was resolved.