I bought some for my Dads Yaris. Mum gets a really bad throat in cars with air con, so the deflectors mean she can have the window down with no draft.
I had a drive in the car and was really impressed. There was no wind noise at all with the windows closed. I then had the window half way down and there was no buffeting and no water came in when it rained. Personally I wouldn't have they myself. I rarely drive with the window open, so they would be rather pointless for me.