Yamaha 1300 Tourer - Yamaha 1300 Tourer Fansite

I would like to add a GPS to my bike for the long trips but I can not see paying 6-8 hundred dollars for the Garmin motorcycle GPS. Has anyone used the regular GPS (ex: Garmin 250W) on a motorcycle? Have you had any issues with vibrations? I am also looking at the Techmount holder, it looks like a good quality product. Any feedbacks would be helpful.

Terry