Most MBA programs have three application deadlines, Oct-Nov, Jan-Feb and April-May. (Do note that most colleges are now doing away with the third round!). The applicants in each set of deadlines are evaluated in that pool and the results are released prior to evaluation of the next pool of students. For e.g., if you apply in the first round prior to the October deadline, you will get your admission results by January.
The “best round” to apply has been a very controversial issue. Several people believe that the second round is the best based on the following conception – Admissions committee is very selective in the first round, as they like to keep their options open for exceptional students applying in the later rounds. On the other hand, by the third round, there are very few slots remaining and hence your application needs to be exceptional.
However, based on our experience, we recommend that if you are planning to apply to the top 25 programs, you should apply in the first round. The competition in the top MBA programs is immense and you may miss out on the opportunity (inspite of a strong profile), just for lack of seats. The only exception to this rule is if you are waiting for information/results that would further strengthen your application for the next round.