TomTom Rider
I've just ridden 10,018 miles across the backroads of the USA using the Rider. As the report link mentions, the cable from Blue tooth to helmet earpiece is short and the cable is flimsy. I snapped mine and had to revert to the far less comfortable earpiece, designed for non-helmet use. It's accuracy was compromised a couple of times, however I ran with a map back up and where I felt Rider was wrong, I used its compass function and my maps.
I don't know of a way to plan a route on a PC then port it to the unit, although I believe this is being worked on, as I would have liked a topographical feature as well as purely road route. The POI feature helped me find lodgings several times and is extremely helpful. I didn't pair the unit with my telephone for weather and traffic reports as I had other systems, although we may now add this for use in the car in city areas.
The main unit wasn't subject to any serious rain (45 minutes total in 47 days) however it did stand up to sandstorms and a swarm of locust/crickets. Finally, the Sun does make it hard to read at times, so the audio support is needed, despite the lipped design of the unit.