If you liked the sound of the 150, get the 250. The 200s is definitely more neutral than the 250, but I always felt the KSA 150/250 amps were, along with their predecessors, the KSA 80 and 200, the best-sounding of the Krell amps because they were less sterile-sounding than the later versions (OK, they are colored in comparison and probably have more "character"). Both should have more than enough power to drive anything you have, although the 250 has a little more "oomph".
