I love my AVIC-N2 but it's a single-din box...gotta use an adapter kit that doesn't completely look right to handle it.
The Pioneer systems are good. My only complaints with my system are:
1) Must have the navigation DVD in when calculating your routes, or to zoom into a map.
2) The Sirius controls suck; Pioneer's XM controls are MUUCH more detailed.
3) Can't change the voice on the voice control prompts (can't swap between male or female voices, or different female voices).
Other than those small complaints, it's very very nice.