I live in Bangalore, in my opinion, despite all the complaints and the ruckus, the best place to live in India. Maybe I don't have much scope for comparison, because its the only place I've ever lived in India but still! I have travelled quite a bit, to Mumbai, Hyderabad, Delhi, and Chennai and I have my own opinions on each.
Mumbai is insanely fast...a great place to visit and party, but I think I might go crazy running around with that intensity in such humidity!
Hyderabad, at this point to me, does not appear to have much character outside of the insanely delicious biryani. There are not many hangouts, and the once magnificent monuments such as Golkonda fort and the Char minar are in need of a lot of attention. I did have a fabulous visit though . Safdarjung museum is a treasure trove of exciting things and a real fallback to a previous area. Ramoji film city was a great way to spend the day and really exciting to actually see sets from specific movies!
Delhi is amazing for shopping - there's nothing you can't get there, nor any budget thats not workable. The chaat's and snacks are yum, definitely not the kind of flavours you'll find here in Bangalore - jalebi in Karolbagh, or paneer tikka in Sundernagar - slurp! However, moving around in Delhi if you;re not fluent in Hindi is a problem. People will be trying to take you for a ride at each and every corner and safety is an issue. Part of what I like about Delhi is the fact that fashion trends are much more up to date and you can wear a lot of interesting things without getting any stares, however this is also fueling the slightly superficial elements of society.
Chennai is madness! Although yes, the infrastructure is better than Bangalore's, firstly there's no way to get around without knowing Tamil. People have been downright rude when they realise you're not from around there, although I do have many great tamilian friends! Chennai doesnt offer much to do, very few hangouts and nowhere much to shop. A good place probably for planning day trips as a lot of amazing culture does surround the area for example to Kanchi to see the saree making or the famous temple. Madurai temple is the most beautiful and inspiring temple I've ever seen.
Now I'm not saying Bangalore doesn't have its problems, because it sure does, but at the end of the day, I've not met anyone from anywhere who's not been able to adjust in our beautiful city! :)