Been playing GTAIV recently btw. Don't really have any problems with the game, it runs smoothly no glitching and GFWL has been behaving.
T A N S T A A F L
GFWL haven't changed much. The hardest part is getting it to work in the first place.
I just hope that if they do release it on PC they'll do it well. GTAIV was one of the worst games made for console and ported to PC, there were tons of issues with it.