Man, that looks tempting.
Three concerns I have.
#1) Security. If I accidentally leave it on the bike (something I'm known to do), what's stopping anyone from just popping it off and taking it?
#2) Touch screen won't work with gloves. Personally I like using the internet radio like Pandora or Slacker. It'd be nice to still able to skip songs.
#3) Sunlight readability.
I don't see a way around the touch screen aspect. Basically my other thought is feeling the audio into my J&M setup and get a Bluetooth remote. I could still use the GPS and rely on the voice instructions (although seeing the map might be nice). But essentially leaving it in the glove compartment so if I do walk away, it's locked up.
Baby steps. I just got my J&M installed.