older Parasound vs new Halo series? thoughts?

Are the new Halo amps any improvement over the old HCA amps?

For example:

PLD-2000 + HCA-2200ii vs Halo P3 + A21/A23

The specs are VERY similar, I'm just wondering if the improvements on the Halo series are mostly cosmetic? Have anyone heard both? Will there be a sonic improvement going from the old Parasounds to the new Halo series?

Thanks