Just started the PS3 version today (
I know late to it) but it doesn't seem like that huge of an upgrade. Maybe less crushed blacks (or maybe that's my TV/monitor?) and a slightly darker/deeper color scheme than the PS3 version.
The upgraded models, IQ, 1080p and 60fps should be a good upgrade over the PS3 version, imo. You'll come across some sections that, while beautifully lit, will strain and bog down your PS3 to painful levels. When I was playing this I was literally thinking "I wish this was on PC" throughout, because it fully exposed how aging the machine was more than any console game I've recently tried.
all things considered both this and the GTAV port up are doing more to "upgrade" the games than expected.
Tell me more about the GTAV port. Are there any photos, vids, details about the changes?