I can say do NOT get the brand Vu. The threads are cut differently than what is on your lens so they turn maybe 1/2 turn, then bind up.
Leica makes the best filters - lensrentals had a big test of light transmission and flare resistance, and Leica came out on top. I actually was surprised, I didn't think there would be much difference with the 'top' brands.
For normal money Hoya makes excellent filters.