Yes I have one - however in reality you need either a four door car or one where the rear windows open.
They are handy - they only down side being that the straps to get wet. And although I found that water didn't actually drip into the car - I wouldn't leave them on for more that the journey.
Same with the bag - you have to remember that it is fabric and although waterproof to a certain degree. it does not offer the same protection as a solid roof box.
I missed mine this year as my current car does not have rear opening widows.
Just got back from 2 weeks in France with these - bought at the last minute before we went for the same reason. I would see the only downfall as them letting some water in via the wet straps in very heavy (extreme) rain in Uk - few drops down my neck. The contents remained dry and everything felt secure despite wind and rain. We don't have roof bars so these were the only option and I would buy again.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.