The GFR-700 looks to be a fairly new product from Adcom (this is the first I've heard of it, in fact). For the price ($2000 list), I'd suspect that the 990/7125 combo ($1900) would likely beat it on sound quality, would give you two more channels of amplification (the GFR-700 only has five channels of internal amplification), and would offer very comparable features. The 970/7075 combo wouldn't offer as much power (although it would have those two extra channels) and probably doesn't have DAC's that are as good, but it's also about $700 less.

The GFR-700 does include "HDMI" support, but I say "HDMI" because it seems to be purely video switching, like the 970 and 990's DVI switching. As far as I can tell, the HDMI inputs don't support audio except to pass the audio signals out to the display device, and even then it's only HDMI v1.0 (PCM stereo). It does look like the GFR-700 may transcode and scale 480i sources to HD resolution (doesn't appear that scaling works with 480p or higher sources, although transcoding may), which is a nice touch.

Two channel gear can certainly do a good job, but for movies with active soundtracks you will not get the full impact of surround. You also will have to jump through a few more hoops to integrate a subwoofer in most cases, although a few stereo units (like the RR2150) do offer subwoofer outputs. If you're already used to surround, you may find yourself really missing it.