Try to exchange the game. The game froze twice within 30 minutes for me one day, but for the other 20+ hours of gameplay it has been fine. I have a 60gb as well.
I had it sit on the loading screen last night and I restarted the PS3 and it worked fine I i have to delete my saved game i'm going to be pissed. I'm at 48% and 23 hours in.
I just tried calling sony but didnt feel like waiting and figured they would tell me to talk to rockstar. I can't find a number for rockstar so I emailed them.