according to my opinion its better to do in medium size firm.. there u can go for various types of audit, u can have frequent interactions with your employer, they will try to find time to answer your queries.. and they can afford you time or leave for you to prepare for examinations too.. u can learn a lot because you are free to interact with the persons in your office and also client office anytime u want.. you will get good support and also deniors to telll you tips.. i have heard it from many of my friends doing articles in medium firms.. but where u join is ur wish and look for ur comfort too..
all the best for future 
CAclubindia
