hi all. once upon a time i was asking the same question...but out of experience i am sayin this..
guys..pls pls dont worry about the firm is big or small, get into anyone first..you can make a small audit firm a bigger one with your creative skills, it is surely an opportunity to churn ur life. in big firms you follow a standard check lists & guidance only, but in medium firms u feel sense of independece of what u do with easy contact with the partner of firm.
where ever you are, just think on your own, learn the skills of stat,tax audits etc..know all the provisions..think like you are one of the partner of firm, make it a happy audit firm.
Big or small you must think everythin BIG, learn in a BIG way, help the smaller.
feel free to contact me at kirankumarCA @ gmail.com