Top of the line is Zumo 595, the 550 is almost the same thing but get your wallet ready for either. Down in price and size is the 395 or 390 but does almost everything you need but it does have a smaller screen. I think the final 5 in the number means it has adventure routes available, don't think you really need those. LM means it has lifetime maps. Older model and still used by many is the 660 but silver and not as good looking as the other two. Don't think it has the tire pressure monitors either. The Zumos are great and you will find many who use them, good for sharing routes etc. Water proof, vibration resistance, left hand controls, screen face accepts glove use, add music and phone compatible they are nice. Base Camp is hard to learn at first but has a huge learning curve and works great after some playing around and reading.
Thanks for the information. Just the kind of info I am looking for. I agree I do not need to many fancy options. Just looking for well built and reliable. Roy
When I said 550 I meant to say 590. The 550 is really old. Unfortunately the options come with the well built models. You could go with a much less expensive non motorcycle Nuvi. You can find some good comparison charts on line of what the diff models offer. I think the 590s are going for just over 7 on e-bay or Amazon, the other one much less. You will also need two tire monitor sensors if you want that and it is good to know your pressures.