I had them on my first mk5, well aftermarket ones - they tend to get broken lenses due to the proximity to the ground, the LED's fade, the camera itself creates a shadow on your number plate and finally, some screw into thin air so you need something behind it such as a plastic window frame spacer so when you screw in the camera it goes into the plastic & squeezes down into the bumper to lock it in place.
It's been over three years since I had one, I guess they have improved. For a couple of hours work once a year, I put up with their shortcomings with them being so cheap and effective once fitted.
OEM ones are probably great.