Just had a Nextbase 512GW fitted to our Kadjar.
Bought it from Halfords who charged £30 to hard wire it to the car's electrics, including the fitting kit. (I think the kit costs about that alone). They did a good job, no wires visible.
Pro's of camera - takes very good quality video, no glare, can easily be demounted without disconnecting wiring, simple set up menu, compact size.
Con's - can take a long time to download video to computer, protect feature seems over sensitive, wireless function not fully explained - not got our's working yet - no paper manual - CD or download only, can take a few minutes to acquire a GPS signal.
The only other issue is that the plastic box on the windscreen which holds the car's rain and light sensors can intrude onto the video if then camera is mounted too close.
Any questions, please ask.