I'm not a pianist, but I've played pianos a lot.

It and small and painless install. If you're even curious, I'd suggest downloading it.
The
biggest problem I can see is that it's got way too many expansion packs. So if you've got GAS, be prepared to go broke if you like the sound.

For a while It was stopping and complaining that the CPU was maxing out, even though the polyphony was only about 10 voices and Task Manager said that the CPU usage was only at 50%. It turned out I had my audio running through RealPhones (studio specialization simulator). Once I turned that off, the problem went away.
I wasn't entirely convinced I was playing an actual pianos. It seems there's
something lacking in the tone.
On the other hand, it's got a nice sound and is
very playable. And that's what really matters, right?
There seem to be enough options in the Stage version for most people. Heck, you can even set the level of disrepair for the piano, which is very cool.