I was running a Hifonics ZX6400 the previous summer rated at 340x2 for my config. the Avionixx has a noticable increase over the old HF.
Be aware that I am running the 2004 vintage tripath amps which were rated at 12.6v, I believe the new A/B amps are rated at 14.4v, it makes a difference.
In all honesty I always take manufacturers claims with a little salt. When I researched the Avionixx most owners noted an increase when compared to similarly powered systems. The other thing I liked about the Avi was the cleanly laid out circuit board.