So far I like it. The UI is simple and straightforward. The analog AM/FM tuner source disappears once you've hooked up the HD tuner module. That's something that annoyed me to no end with the Sony. You'd have the HD tuner module hooked up, but then you had the dead source (the analog AM/FM tuner source) that did nothing once the HD tuner was connected. On the Sony, the analog AM/FM tuner source selection stayed there even with the HD tuner hooked up.
The sound quality is much better than my stock HU's even though I'm still using the stock speakers. I've installed a 10" sub. in my hatch / trunk floor and it rounds things out nicely for now. Still trying to decide on what I should get for the front (I want components) and for the rear (3-way or 4-way coax. set). Front and rear speakers need to be 6.5". I have a separate thread on that though.
A nice feature of the P8000BT is that you can connect a USB flash or hard drive to it OR an iPod. When the iPod is connected, the P8000BT takes over its control and you control the iPod through the P8000BT. One of the neat features of the P8000BT is that once is has taken over the iPod's controls, there's an option to let the iPod be controllable on the iPod itself at the same time the P8000BT has control of it. Sort of a dual control option.