For uv filters I prefer b / w, since the coating is much better than the leica, you can literally see the difference with your own eyes and not to mention they are also thinner than the leica.
I even like Hoya better since they have the same quality with less price. However its just my sickness that I wont put a made in japan filter on a made in germany lens. No offense.
I only use leica when there is no other options.