If you like larger touch screens and generally keep your GPS hard-wired to the bike, the Zumo's and the waterproof Nuvi are good choices. Personally, I'd probably spring the extra for the Zumo as it's a little more optimized for motorcycle use.
But you can do everything these units can do (and sometimes more) with one of the handheld Garmins like the 60CSx. They're more portable, are easy to swap between vehicles, and it is feasible to run them on battery power without hard-wiring. But the screens are smaller, the interface is small buttons, and you have to spend more time figuring them out. And then need extra-cost maps to be useful. Personally, I like the 60 (and its 62 successor) a lot - one of the best pieces of consumer electronic gear I've ever bought. But it is not for the casual user. The Nuvis and Zumos are a lot more simplified (some would say "dumbed down") for the casual "just take me to this address" user.
Costco has the 60CSx on sale right now for $200 brand new.
GPS choices abound with complex tradeoffs. You're not just buying into a GPS - you're buying into a complete GPS ecosystem of hardware, software, databases, users, support, updates, swapping routes, third-party maps, etc. This forum on advrider.com is a good place to wade in if you want to study.
http://www.advrider.com/forums/forumdisplay.php?f=75
- Mark
