Yeah, my GPS has been pretty much unusable in Cognition 4.1.1. I think it was better in 3.04 before the supposed "Adam's Fix".
In general I'm tired of people saying their GPS is working in custom ROMs when all they do is stay stationary and see how quickly they get a GPS lock. It's relatively easy to get GPS lock and be reasonably accurate. However, it's completely different story when you put the GPS to work when using the Google Nav and try to drive around. My GPS keeps losing the signal and the Nav app keeps rerouting you because it thinks you're on a different road than you actually are. This makes my Captivate completely useless as a Garmin/TomTom replacement.