I only have experience with the Avantera having listened to it couple of times at a friend's place. Typical German quality - neutral, clean, detailed and dynamic. It hits hard and go low down the frequency spectrum. There isn't any disjoint between the side-firing woofers and midrange drivers on the front baffle as the transition between the bass and midrange is quite seamless. It seems as if there is no character to the Audio Physics, an absence of "house sound" that is inherent in most loudspeakers making each and every one of them distinct and unique.
I have not heard the Avalons but do know they are excellent speakers as well. At this sort of price range an audition will be necessary. When it comes to speaker selection, all bets are off as listening preferences, room and equipment matching come into play.