Sorry if this post is redundant, but after searching for awhile, I haven't found a clear answer.

What is the best gps system for using in China? I'm particularly interested in maps of the NW. After discovering that paper maps are all horribly inaccurate (at least in NE China) I decided I'm gonna invest in a GPS. I'm in America for the next 3 weeks, so I wanna try and buy a good one while I'm here. Please let me know if you have any suggestions or useful experience.

I read about people using cell phones, but I think in the end I wanna get a good water/dust/vibration proof unit that I can stick on the handlebars, and read in bright sunlight.

Thanks.