I also got my Arkon mount from semsons.com.
Arkon mounts are great and their customer support is also top notch.
Once I had a broken windshield mount. I send them an email to request for a replacement. To my surprise, I didn't have to send in my broken mount. All I need to pay is the shipping and they send me a new mount.
I am thinking of getting the new Arkon bike mount. Has anybody tried it already?