I just recently got mine. Coming from a NAD D3020 stereo amp, the sound quality of the RZ30 is at least on par if not better. I had a Marantz Cinema 70s for a couple of weeks but was not satisfied with the sound quality of that amp so sent it back. The RZ30 is much better than that. The screen of the Marantz was nicer and the remote a 100 times better than that of the Onkyo though.
I bought the bass control for it aswell. I only have one sub atm and I have not been testing it for very long yet but it seems to work nicely.