I feel qualified to talk about this, because, one, it's my blog :-p and two, I've lived in both Bombay and Chennai for fairly long periods (10 and 4 years).
Both of them are pretty amazing places to be in, to live in. But, Bombayite at heart that I am, Bombay still rox.
Why? It's fast. Imagine yourself hovering in the air above V.T, and above Chennai Central. Okay make that Mambalam station, which hugs Ranganathan Street [R.S] . At rush hour, the size of the crowds at R.S and V.T are similar, but the R.S crowd is almost glacial in comparison to V.T.
Other points of comparison are fairly moot. Booze doesn't matter to a teetotaller, and squalor is a fundamental right of all Indian cities, as are grubby commuters/vendors. The Hindi squabble is best left alone - personally, I think all Indians should compulsorily learn Hindi up to 10th. The "deal with it" attitude isn't going to win any friends...And to be fair to Karnataka and A.P, whenver I've been there, the amount of Hindi spoken by the populace has always impressed me. OTOH, the amount of Hindi here [in Chennai] is bordering on the microscopic.
Travel then. The public transport system in Bombay is any day better than Chennai, where you're pretty much stranded on a remote island if caught out past 10 p.m without private transport. And yeah, the auto drivers here completely empty your pockets. *EVEN* if you're a local. Rs.30 here for a Rs.15 distance in Bombay. And it's actually a poor reflection on the State Government that it doesn't step in to do something...[where something == enforce the meter system] The buses here though, what can I say? Chennai buses rock! Literally and metaphorically. The green, monstrous khataras do compare with cycles without rubber tires, but you also have the 'luxury' buses that charge double, and do actually offer a pretty fast, smooth ride. And the bus network is amazingly widespread, with service to even some hidden corners.
All in all, I think the general public in Bombay are infinitely better than the weirdos in Chennai, who really tend to spoil the public transport experience here. [rant alert] I mean, live with it, if it's crowded for you, it's crowded for everyone else. Don't grumble, or blow your top 'cause someone elbowed you. For all of Bombay's famed peak-hour train mobs, it's quite easy to get in, stay there, and get out in a totally composed manner... [/rant alert]
Real estate costs in Chennai are way lower than Bombay, which explains why people get the illusion that everything's easily accessible here. In Bombay, only the very early movers and now the upper middle class and above get to live in the heart of the city, and its innards. In Chennai, I can fairly easily get a house in Mylapore, or Ashok Nagar, or some such other 'city' place. Both my Bombay and Chennai houses are outside city limits, so I have a fair idea of what I'm talking about. Commute times are pretty much the same. About 75 minutes from Chromepet to Tidel Park. About 75 minutes from Thane to Churchgate. End to end, average times.
I'm pretty much on the fence on this issue, with a very distinct tilt towards Bombay [the pace, man, you have to experience it to believe it, it gives you purpose in life], I'd say that whether you're an ardent Bombayite or a fanatic Chennai-ite, as long as you keep an open mind when going from one city to the other, I promise you, you'll absolutely LOVE the experience!