I have had a Zumo 450 for more than a year now and love it! My Harley GPS owning buddies are envious. I remember having to stop on the side of the road for them to be able to read and operate their Harley GPS's. My Zumo is strickly "shift on the fly" and the MP3 player compares to none. I use Sony Fontopia earbuds and it sounds like the music is coming out of the sky! I ran an extension for the headphones under the tank and seat so the wire comes up may back. The large bright screen adjusts itself from daylight to dark and has big buttons for fat gloved fingers to operate. I believe the only difference between the 450 and th 550 is the blue tooth feature,... Who needs that! By the way, Harley has introduced the Harley version on the Zumo 550 in their new 2009 catologue. It is, of Course!, overpriced Harley merchandise. Look for a 450 on eBay for the best deal.