My wife has the Axim X50v with the blue tooth navigation option. When it works, it works great. We've had a few issues with the Axim talking to the GPS device. I can usually get it to work by resetting the Axim. It has built-in WiFi as well as the bluetooth.
If you are going to use it for more than just GPS, I think it is worth it. If you're just looking for GPS, maybe look for something else.