Had one added 2 days ago. Sensors look good (sensors look just like on the back of a Five Hundred), not as good as without, but they aren't too distracting. Function wise it is about like the factory systems as it beeps faster the closer you get to an object. Interior speaker is a little ugly, but its by the drivers right knee so unless your looking for it you wouldn't notice it. I know there are other kits available also that woudl have different speaker/switch units.
I've very happy we added it since I'm sure I'd have backed over something eventually. I still haven't learned to completely trust it since it looks like I'm about to back through the wall when I try to back close, but it does work and I'm happy.