I personally prefer the 3 full sets. In the YCTA last year, we went to 2 sets with a 3rd-set tiebreak in the Spring season due to limited court availability last year (due to a number of the regular facilities all being resurfaced at the same time). I expect we'll return to full 3 sets this year; especially since the Spring season is the only season where 3 sets traditionally occurred in these parts. I was told the summer heat caused mixed to be shorted to a 3rd set tiebreak. I also heard somewhere (I think it was the tennischannel) that the ATP and WTA were considering experimenting with moving to a champions tiebreak to decide matches (two reasons I heard were to add a level of "sudden-death" excitement, as well as to help to minimize player injuries that are the result of the wear/tear of too many long matches being played during the year).
Imagine Federer or Nadal folding in a champions tiebreak to a lucky loser!