Virtually all top schools as far as I know have a "staged" admissions process - which means that they don't review any applications for that round until the round deadline has passed. For example, if the "Round 1" deadline is say Oct 31, then they won't review any applications submitted on or before Oct 31 until Nov 1 at the earliest (and will get the decisions back to you by a certain date - usually on the same day for everyone in that round in a mass emailing of rejections, admissions and waitlists). So whether you submit right on Oct 31, or Oct 14 or Sept 15 - it won't matter. It just sits in a big pile until Nov 1 and then the pile gets divvied up to the various individual adcoms for review.
The only top school that works on a "rolling" admissions basis is Columbia - which means that they review the applications as they come in. So in Columbia's case, the earlier you submit, the better.
Alex Chu
alex@mbaapply.com
www.mbaapply.com
http://mbaapply.blogspot.com