I would personally go with a Pioneer AVH-P6600DVD. You should be able to find it for that same price. If you can't, come to Cincinnati and I'll sell it to you for that price.
The reason I say this is because Alpine has an impossible system to ground out to watch video while moving. So forget about watching DVDs without the ebrake. The Pioneer on the other hand, well, it's easier to hook up so you can watch the video while moving than it is to hook it up properly.
The pioneer also has a much wider viewing angle, and typically last longer. I see alot of service on the Alpine unit.