Sonus Faber, Opera, Vienna Acoustics, Usher Audio

Concur with Lrsky's assessment between Sonus Faber and Viennas's rich and warm sound. However, I think SF is a more laid back than Viennas, while Viennas are little more forward/in your face and the bass is more weighty. SF is easier to drive. They are both great speakers, pending on your musical preference. My assessment is solely based on an A/B comparison between the SF Grand Piano's and Vienna's Beethoven.

I have a pair of Vienna Acoustic Mahlers. The sound of them with really good electronics, is remarkably good.
I am fortunate enough to have Halcro driving them right now, and would say they can be great fun.
The bass, has a bit of a built in loudness, even when set to the flat position. But on many things it sounds ok, and doesn't seriously smear up into the mid bass regions.
The dynamic contrasting is good, and staging is very good to excellent.
The Sonus Fabers are an extremely refined sound, oddly like many Italian things, seem to be.
I love both, and think you couldn't go wrong on either side.
Best,
Larry

Take a look at the Usher 6 Series. They tear up both the Sonus Fabers and the Vienna Acoustics....especially at their price points.

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!