Round 1 is statistically definitely the easiest, our experience on here last year backs that up. The quality of the applicant and application probably does have something to do with that though. Many people applying R1 have been putting a lot of time into the b-school thing so they may be more qualified or at least better prepared. I also tend to think that in a time with huge jumps in applications schools arent sure how the different rounds will play out so they play it safe, probably a lot of WL folks are the people who in past years would have made it in.
That said apply to the earliest round you are ready, but remember applying in R3 (or R4 at some schools) is nearly impossible. Some schools are almost completely full and a person on the WL who is equal to you will get in over you most likely.
Kellogg Class of 2010...still active and willing to help. However, I do not do profile reviews, don't offer predictions on chances and am far to busy to review essays, so save the energy of writing me a PM seeking help for these. If I don't respond to a PM that is not one of the previously mentioned trash can destined messages, please don't take it personally I get so many messages I have a hard to responding to most. The more interesting, compelling, or humorous you message the more likely I am to respond.