Outlaw
I haved not heard the 7770 but had the 990 for a couple of weeks for eval. The 990 was a class below my other two candidates (EMOTIVA DMC-1 and Parasound C2) but had some nice features (like very configurable bass management). It was a much less expensive unit so from a value standpoint, it is a good choice.
Up until yesterday, I would have reccomended the Emotiva (for the price) but AV123's split with Emotiva puts that brand at risk (IMHO).