EssaySnark says, apply in Round 1.
For whatever reason, this point is debated on many blogs and discussion forums (by people who are NOT adcom members). However in our experience – tracking data from many years of admissions now – it is easier for the masses of decent candidates to get accepted in the first round. A superlative application will get an offer in any round – even round 3. A flawed application will have trouble regardless of when it’s submitted. It’s the on-the-borderline and more average-type folks who benefit the most from a Round 1 application.
Meaning, if you’re GMAT is in the 710-ish range.
Or your GPA is around 3.3 or so.