Has anybody actually compared the smaller backup monitor that can be added to the 2012 Toyota Camry LE via the rearview mirror and the monitor that can come with the XLE, as viewed in the 6.1-inch display screen? No dealer around here has had the add-on version, so we can't try it out. It seems more natural to be looking up at the mirror, but I'm wondering if the smaller size would make much of a difference. (And, yes, I know that you can't just depend entirely on the monitor when backing up but must look out the windows to the sides, etc.) Does the mirror version automatically appear when the car is put into reverse? Are the cameras positioned the same? Any other considerations?