sc vasudeva, sp chopra, sr dinodia, ss kothari and tr chadha ...all these are good firms.
All these firms have good PSU's clints in their bucket, they have diffrent team for different job profile such as Internal Auditing Team, Statutory Audit Team, Taxation (Indirect Taxation & Direct Taxation) etc
Some of these firm have good Taxation Team but not Auditing and vice versa. You can select among these on basis of kind of profile they are offering or they are agreeing that you will get your desired /interested area of training.
For better Taxation exposure you can go with SS Kothari., SNB (Sahni Natrajan & Behl).
For Auditing exposure you can join TR Chadha or SS Kothari.
Shubham sir have explained very nicely,,
i would be suggesting TR CHADDA,,
my roomie is a article there,, and he is getting good exposures of internal audit and statutory audit...