I wouldn't get to scared. I have no problems with GPS or anything else major. The stuff I don't like has to do with the custom email app, a couple calendar issues, and some IO lag.
We know Samsung is working on the GPS, and my guess is that they are working on the IO lag issue.
This software is not an update - it is a BETA ROM that was leaked.
The captivate is no worse then any other new phone that has come out. The Droid X, Evo, iPhone have all had their share of bugs, and they all usually get ironed out - except for the design flaws in the iPhone - but that is what you get when you make a phone 90% glass and wrap the antenna all the way around the outside edge.