Well, the screen is really to small to use while riding, with no external antenna it looses the sat's under medium tree cover.
Other than that it works great! Great battery life, it is water proof (I lost it in a stream once and after 15 minutes found it and it was perfect.) I just have to stop sometimes and try to figure out if I missed a turn or what every now and then.
If you want one to use while riding find one with the largest screen you can afford. That is the most important thing I have found. Oh yea, mine is an older one. (no color screen so I don't know about that one)
What I am thinking about doing right now is gutting an old laptop and mounting the screen on the dash and just connect the GPS to it using MapSource and just cram the rest of it somewhere on the bike. Then I have have a 13" screen GPS.
To download routes you just have to hook it to a computer either USB or serial depending on the model and have the route be compatible with Map Source.