A few points:
1 - mp3car.com is about installing computers in vehicles. We eschew units like the one you linked to in favor of a full on PC. You're likely to get opinions and reviews on this unit elsewhere.
2 - I wouldn't buy it. If something goes wrong, who are you going to take it to for troubleshooting? The Ebay seller? The manufacturer? Do you even know who the manufacturer is?
3 - Quite simply: You get what you pay for. That applies doubly so with electronics.