I have seen one in person at the dealership where my wife was working at the time. It was very well installed but the area around the spine looked a bit odd.
I personally do not like them, I think if you rolled the car, god forbid, it would be a weak spot and have weakened the roof as well.
We have one on my wife’s Hyundai and it has never been used in ten years. If she wants fresh air she opens a rear window and forgets to close it at times, it was open in a rainstorm once but the wind came from the other side of the car and inside it was just a little damp.
I would never decide on one as an option.