The selling point for me would be if it makes branching, merging, and tagging easy. The day-to-day stuff (add, commit, update) is easy enough to do with the command line, Xcode or BBEdit--I don't need another GUI tool for those. It's the once-every-couple-months operations that I really need help with. I want a program to walk me through the things that I'd otherwise be spending a half-hour re-reading the manual to remember how to do. That's what brings value for me.