You will regret getting a cheap & unheard filter brand (because i did). If you can afford the 16-35 L lens, then i bet you can get a better filter for your lens. Better be safe than sorry. Poor quality filter sometimes or most likely will degrade your image quality.
B-Man - I think you had better do your research. It appears you are misleading Janne though I do agree with your statement about poor filters degrading your image
Marumi is NOT unheard of. They have been around since the 1930's, Marumi Optical was formed in 1952 for starters. See more below on the Polarizer especially.
Janne, though you don't state which filter type you are attempting to acquire I can start you off with a few links for a UV and a Polarizer that may help. Note the degradation on certain filters via the charts and photographs. Suprisingly, Tiffen came in dead last on one of their specific UV filters - see the photos as to how much was lost on the original photograph with the use of such a filter.
UV Filter Test: http://www.lenstip.com/113.1-article-UV_filters_test.html
note the specific Hoya that came in on top (there are various types). Link #4 will take you to the finalists.
At this link: http://www.lenstip.com/115.4-article-Polarizing_filters_test_Results_and_summary.html
for Polarizers, note B&W and Marumi were tied for first though Marumi costing considerably less. I have this specific Marumi Polarizer in various sizes 82mm, 72mm etc. The Marumi's work flawlessly and I have done my own comparisons as well - no discerning degradation and no vignetting. You can get them the cheapest from an Ebay store called: Eventcameras. I've bought from them numerous times - excellent service, Ben always replies and their prices can't be beat. he also carries the Hoya and various other brands. Ask Ben for his thoughts on Marumi as well. As a distributor he can carry whatever brand/model he wants and he is very knowledgeable
A final note is don't always believe the more you pay for a filter the better it will be. I recently owned a filter that was over $300. It performed horribly and back it went the next day.