Just FYI, the new line of TT GO units has been presented at CeBIT last week. They should become available by May in the UK. So the choices now are ONE, 510, 710 and 910. (and the Rider for motorcycles). All these units have the new SiRF Star III chipset which makes a tremendous difference with regards to reception quality over the former chipset which was implemented in the Classic, 300, 500 and 700. I would advise you not to buy any of those units anymore, but rather wait for the new ones to arrive.