I have B+W F-Pro on all my lenses. It's the MRC UV10 and have been happy with them. I just replaced the Quantaray Professional Series on my 24-70 with the B+W version. There was nothing wrong with qray, just doesn't seem to be constructed well. When I clean the glass, it doesn't seem to sit securely in the ring and dust seems to always get inside. For those of you curious, Hoya makes the Quantaray Professional Series. Perfectly good filters with good quality glass, just lesser build quality compared to B+W. B+W's are pricey, especially when I had to get one for my 16-35mm f/2.8L II which uses an 82mm filter size.