Depends upon the nature of audits that you are assigned. Some firms BIG or SMALL have the tendancy to get you stuck up in any one/two kinds of audit work. Try to get maximum exposure in as many areas as possible that the firm is involved in.
Look for Big firms, if you get admitted into it fine. Its always good to add a Big firms name in your resume... While you are working there, find out if u will be involved in all kinds of audits, if you are not allowed, its better to quit and join some other firm..After all we have to look at our future first..
U are right, in small firms u wil get time to learn, in big firms u might not get that much time......yet, if they allow study leaves then that wont be a problem.....U shld be allowed leave for both exams and classes too.......