I have both.
The Steinway is more versatile and has a greater variety of tone, especially at soft velocities, but it's a little more difficult to play. I think something is slightly off in VSL's scripting on the Steinway so that it doesn't always pick up the midi data as seamlessly as their other instruments, particularly in fast passages. It's by no means bad, but noticeable from time to time. I still really like it though.
The Imperial has slightly better playability and and is extremely even and clear, but is less colorful and offers less tonal variety. But the base tone itself is very attractive and distinct. I much prefer it to the 280VC, which is a lot brighter and harder sounding.
These days, however, I tend to use the CFX most of all the VSLs. I initially didn't connect with it when I first demoed, but after giving it another shot a few months ago it's become my favorite of all the modern grands. Really versatile, with a lovely tone and superb playability. I also love the Bluther, but that is more of a vintage sound.
I demoed the new Fazioli over the holidays but did not like it at all. Very tonally limited with a thin, smallish sound. Hard to believe it's a 10-foot grand. Would avoid unless you really have a thing for Faziolis.
