Sonus Faber, Opera, Vienna Acoustics, Usher Audio

Fabers and Viennas sound, similar. They are rich and warm, almost like a well tuned instrument themselves.
They are excellent.
I have a pair of Vienna Mahlers that I am selling some time soon, at a greatly reduced price if you have any interest.
Best,
Larry

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.