Gotcha, thanks. I forgot you actually had the 28's.
I don't know about Parasound's design philosophy but with Bryston there is no good, better, best per se, only differences it watts and slight differences in design to achieve certain things like with the monos being bridged designs I believe so the 28's aren't really their flagship just the most powerful items in the lineup.
Most differences in sound people hear between models as they go up the lineup in my opinion is most likely simply Class A vs Class AB because as you go up the lineup in power the amps stay in Class A longer as they are all Class A for roughly 1% of the rated power I believe.