I was not taken aback by the sounds to be honest. The piano is gobsmackingly good and sounds very sweet, and the digital-sounding synth sounds shimmer nicely enough. The problem it has is that analogue-style sounds are very weak. It takes a fair bit of programming and fiddling to get what you want, and despite programming it being so much fun you wish it didn't take forever to get results. The drums are solid throughout.
Acoustic drums sounds realistic, electronic drums have real kick.
To be honest it would have benefited from the original samples placed in it being a bit thicker in some places, as the acoustic modelling can sound nasally when trying to cover these up. One thing is for sure, and that it has a lot of character. It has been mostly very reliable and pretty robust too. I dropped a speaker on it once to my complete horror, but it appears to not even have noticed. I've never had it lock up, apart from when MIDI transfers have gone wrong and here for some reason I have encountered more problems than I should have.