I need to buy an after-market GPS for my car, but I'm a novice in this area. Because of vision problems, I'd like at least a 4" display, voice turn-instructions and it's got to be dash-mounted. But most of all, I want reliability (in its routing-directions and its build-quality). Which brand do you recommend? 1. Cobra 2. Garmin 3. Lowrance 4. Magellan 5. Tom Tom 6. Other ------------- PS. I chose 'Other' so that the results would be visable to me.