Angel, I have this exact setup (the monitor is built into the rear view mirror). I had Rob install this back in May when we had to bring our van up to Fresno to get some fixes done. It has been great, especially for judging the distance between the rear of the van (spare tire) and any objects that are approaching like a parked car, sign or boulder. I can see things clearly without any problems.
One thing to consider though is getting a radio system that has a DVD, GPS and the monitor built into it. This would be less expensive and a cleaner install than purchasing separately. However, it is expensive and if you don't need the DVD and/or GPS it is not worthwhile.
2007 Ford RB Diesel SMB 4x4 Pueblo Gold; Custom configuration (aisle layout); PIAA 580 driving lights; Picked up on Oct 19, 2007.