I'm a Garmin fan. For the bike, I have a Garmin Zumo 350 with lifetime maps. The mount works well, it stays on the bike, as it's hard-wired in, making the connection waterproof when the GPS is in the mount. It has the option of also connecting via a mini-USB, so it can be used in a car. IMO, the car-only units won't hold up to the demands of being on a bike. The Zumo is vibration and waterproof, and it can be bluetoothed to blue-tooth compatible headsets, so you can hear the directions. I'm very happy with it.