Also, it's worth pointing out that a full disc doesn't always mean the extra space has been put to good use. I've seen a lot of games (on other consoles) that have a bunch of random garbage just to fill up some space.
I'll be surprised if the audio and video doesn't absolutely blow me away on PS3. I have a 360 as well, so I plan to compare them both and see the differences for myself.
Not that I disagree, but on the flip side, they could have reduced the size down to fit on a single layer, so I'm glad they didn't do that. We haven't seen a 360 release yet, so it's a bit early to say whether the PS3 version suffered (eg. 360 could be compressed and on 3 discs).