If you can afford it, go for the factory fitted unit. Heard after market is around 45K, not sure if it includes cameras or not. But the issue is whenever your dash board or doors are opened for any sort of mod/addition clips will not go back as same as new. So there is always the risk of some squeaky noises afterwards.
Factory fitted unit has three cameras, front, back and one pointed towards driver. Did not like the result of the camera but heard there is a protective plastic cover left on it from packing on it, if removed it improves alot. In other respects just a android tablet optimized for your car. Will get my car in 2-3 weeks inshallah, hopefully will find out more then. Opted for the 4yr extended warranty so will try to keep it as stock as possible, only plan on making it 10H ceramic nano coated myself.