I recently went through this situation myself, and listened to the Bethovens and Mozarts (Vienna) and the Grand Piano's from SF. I went with the SF because of its clarity, smoothness and open mids and highs. The low end on the GP's does not compete with the Vienna products, but its a matter of personal listening prefference. Either company has great offerings and you should give both companies a long listen with a wide variety of of music. One thing to keep in mind is that the SF products will play more easily with less ampification than the Vienna products. Good luck!
