I also have a Pioneer AVIC-N1 in my Gen II RT/10. I'm fairly happy with it. When I researched it (last June), it was by far the best bang-for-the-bug dash-installable AM/FM/CD/MP3/DVD/Navigation system out there. (I installed the antenna in the sport-pad - the pad in front of the roll bar, by hollowing it out).
I also own a couple of Garmin units (StreetPilot 1 recently sold, StreetPilot III, Etrex Legend, and a number of older units), and I must say that the Garmin units are more convenient when it comes to figuring routes, but they can't play MP3 CDs, DVDs, etc.
The DVD player entertained my copilot for most of the 50 hours of driving to and from VOI8, which the Garmin units wouldn't do.
All in all, I'm happy with it, although it could be improved. Main drawbacks to the Pioneer unit are
1) having to insert the map database DVD (one for the west half of the US, one for the east) whenever you want to compute a route, and
2) it does an incredibly bad job of figuring long distance routes - for instance, the route it figured from San Jose CA to VOI8 was about 200-400 miles out-of-the-way, no matter how one configured the average speed per type of road - it insisted on taking me through L.A. and OKC, both of which are out of the way.