Satpak- First off, congrats on being close to the 'dream' house... I do real estate on the side, so just my general thoughts:

USAA- great for a lot of different things, but not necessarily the cheapest (although if you use the mover's advantage that may help narrow the gap). Also, I have had issues with them being overly conservative in their LTV calculations. Makes for a fine business model and keeps their doors open, but has left me in the lurch.

Low/No money down: I try to keep a healthy cash reserve at all times...
One thing you may look into is using the VA, which, if you qualify and if the VA is not closed by gov't meltdown could help you with the low down and avoid PMI. My experience on the 100% financing has been that they make their money in other ways (fees...) but if it is a hot program please pass it along. Good luck!