The Worth K Master. Unfortunately the TSSAA (Tennessee's governing body for HS and MS ball) has mandated a switch to the Wilson NCAA ball for the coming seasons.
I like the Worth Dream Seam as well. Mine get a lot of use between lessons and practices, and I feel like they hold up the best to extended use. Some of the others are fine for a game, but eventually get pretty slick. The Dream Seams (NCAA ball) seem to keep their tack.