Vienna Acoustics Beethoven Concert Grand vs Sonus

no, they are distibuted by the same company. the pianos are in a different league

I think up to the Mahlers the VA are better, but then the Sonus keep getting better.

I have not heard the Sonus, but heard the VA and fell in love with them. Hard for me to describe, as to me speakers are the most subjective component, but I loved how deep and tight the bass was, the imaging was great, and the crossover network that uses one of the large drivers to augment the midrange adds a depth to instruments like saxaphone as well as vocals that I found very pleasing. To my ears they beat comparably priced offerings from B&W, PSB and Thiel by a modest margin, and several others by a much wider margin.

I am buying the Concert Grands - and adding the center and surround as well. Power for the fronts and the REL 528 will come from a McIntosh MC602SE. I cannot wait to get my room set up (after a basement remodel).