It just didn't make sense to us to move to Boston when we already have an office in SF, so we opted to apply for the winter round.
I guess one argument against waiting would be that moving to Boston away from SF (and all its known distractions) would let the team totally focus for the three months on nothing but work.
I didn't bother with the winter round because I live in Massachusetts and have family and friends mostly in New England, and it seemed silly to move across the country rather than waiting six months and moving across the state.
I have decided to move to the Bay Area.... then I can prolly apply again.... my idea is great and I am still lookin for a co-founder...