Note: there are several Chowpaty restaurants in the Westlands/Parklands area. I believe they are all under the same ownership. This review is of the Westlands location in Shimmers Plaza).
The menu has South Indian, North Indian and some Chinese sprinkled in. I think one can get better North Indian elsewhere (albeit not as cheap) so I focus on the South Indian. Chowpaty's strength is a wide variety of dosas, each of which comes in 2 formats: plain (no filling) and masala (potato/onion filling). Get the latter in order to be satisfied. The dosas come with a coconut sauce and with sambar - delicious. The puri is also good.
Despite boasting an army of waiters, service can be slow when there are many diners, but the waiters are friendly. Beware: parking is a nightmare at lunchtime.