Just watched it and it was good fun. Thoughts:
Ranbir is an unapologetic player. He cannot stay committed and has no intention of trying. It seems pretty apparent that he's very over Deepika and it's also pretty apparent that he and Katrina have something going on. Which is all good... as long as she does not make Deepika's mistake of being serious about him. His passion for Katrina will fade and he'll move on and leave her behind too. She'd be wise to remember that and not take this 'relationship' too seriously.
Ranbir and Sonam have had a serious fall out. He ranked her last each time there was a comparison, he doesn't think much of her career (see his total agreement with Imran's more movies less mags comment) and generally dismisses her each chance he gets. Interesting.
Imran acquitted himself very well in my view. He's the complete opposite of Ranbir; he's clearly loyal and not all interested in the bedroom escapades (but his fiancee didn't come across quite so well frankly) but he's got a mischevious sense of humour and all round likeability that Ranbir does not possess. I think he was the highlight quite frankly. It's good to know the good guys don't always finish last in the charm department.
Ranbir is probably the better actor but I feel Imran will have the more stable career. Just a gut feeling.
7