My Linksys DMA2200 arrived today, thanks to the Media Center team at Microsoft (Thanks, folks!).
I was fortunate enough to get to test a competing product, the D-Link DSM-750, prior to this.
PRO: The single biggest advantage of the DMA2200 over the DSM-750 is a built-in DVD player. This is a 1080p upscaling DVD player. Sadly, you have to exit the Media Center Extender UI to get to the DVD player, but........ Its an inconvenience, not a show-stopper.
PRO: The UI in the DMA2200 seems to be a bit snappier and smoother than the DSM-750.
CON: The DMA2200 does not have the Windows Media Connect feature of the DSM-750. This allows you to access shared music, movies, videos and pictures across your LAN. Of course, you can do this within Media Center, too, so I don't see this as any big loss.
The DMA2200 does what you would expect a Media Center Extender to do, and so far, does it pretty well. It presents almost every function of the full Media Center Experience, and does it in a small black package. No need to have that clunky PC in the den or living room any more.
Both units support Draft N wireless. as well as wired ethernet. And they both support Composite, Component and HDMI video. Surround sound support is standard for both units, as well as S/PDIF audio out. I haven't tried the wireless yet, since I already had CAT-5 running to the devices location. All in all, if its a choice between these two units, I'd spring for the extra bucks and get the DMA2200, as it doesn't lose anything I'd miss and gains a DVD player.