Fannie, Freddie, Ginnie (VA/FHA/HUD), Countrywide Wholesale (CLOUT), Indy, Wells Fargo Wholesale, Option One, Aurora... They're all on AUS now. Pretty much you can only get a live underwriter if you're in a true "they have no credit score" situation.
Credit Scoring has been around several decades IIRC, it's had plenty of time to be found accurate as a predictor by its users. Which is why more and more risk-based servicers are going to it.
I guess I don't understand why the "mystery" (oooo.... scary unknowns
) is such a big deal when getting and keeping a decent score is so simple. Who
cares if one metric gives 10% weight to a 15 month old 30 day credit card late and another uses 9.5%? Check your report for errors once in a while, have a few open lines (with or without balances) and pay your bills on time. Voila, decent score.
Well, the automated underwriting thing only works with a Fannie/Freddie loan and now probably some proprietary stuff, like IndyMac. With Fan/Fred you can request them to set aside credit score for some good reason. So it doesnt matter what kind of standard they use because you aren't going to get the loan any other way.
I also suspect we have not had enough experience with credit scoring yet to say how accurate it really is.