I am sure you have either read a ton of reviews already or listened to people drone about it. I am not sure how much I can add to the existing mass of 'literature' out there. But never the less, at the risk of being redundant, I'm gonna throw in my two cents (err...let's pick rising pence instead).
All the nice things: It's nice to see irreverence to historical cliches in a movie tradition where parody usually means wars between fans. Nice to see actors willing to parody themselves indicating a high level of self-confidence and identity. Nice to see a montage of all those new media. Nice to see Bollywood throw parodical light at themselves although it seems like one giant self-congratulatory, self-reveling party. etc. etc. and all other good things you have listened about the movie in spite of the movie driving itself speedily into a huge-bollywood-cliche-spiral by mocking one in the first place.
Its a Bollywood movie after all, and it remains loyal to all the elements that make one: Changes genre gears every 10 mins, songs for no particular reason which are totally incoherent and anachronistic to the genre of the storyline, fortune-cookie-ish punchlines like 'Dil se Maango, Mil Jaayega; Film Abhi Baaki Hai' and of course all that super-star smugness.
I would have loved to see more out-and-out mockery than frequent shifting gears. The movie should have hung on to MORE cliches and made buffoonery by using elements like "Making Sandy realize that she was Shanti", "Maang Bhari Sindhur and Chutki Sindhur scenes sponsored by Maybelline Cosmetics", "SRK watching a DVD of Karz and realizing his past life (instead of frequent fire nightmares)". That's something for MTV short film, I guess, if only it had the equal audience, budgets and access to star cast.