oh, I definitely wouldn't return it for any of the issues listed. I came from a rooted, overclocked Droid and the Fascinate is just amazing. The backlight isn't an issue until you're in the dark and trying to guess where the buttons are and it's a slight annoyance that google doesn't make the manufacturers stick with a uniform order of the buttons.
As for GPS, it's definitely an issue for a lot of people. Mine works fine as long as I've used it recently but if I haven't used it for an extended period of time, it's like it clears everything out and has to reset. If I go into maps, select an address and choose Navigate, it will sit on Searching for GPS for 3-5min. Only really a slight annoyance for me since I have a general idea of the direction I need to go. Oddly enough the lock has been fairly quick today. Guess I didn't leave it idle since I messed with it last night and this morning so maybe I'll leave it alone til tomorrow afternoon and check.