I got a june tailor .. tossed it after only 6 months. then got the green Olfa ..... It smelled awful ( like a skunk) . It spent a year in the garage , then I went to International Quilt show and went to the Olfa booth, spoke with one of the reps . they suggested I put it in the tub and soak with vinegar ... that did not help. ( by the way there was a distinct odor in the Olfa booth).
Back to the garage with it ... after about 6 more months it was finally able to be used.
I have two self healing mats the Olfa and a gray one ( not sure of the name, but it does not smell) both perform well , but like anything it does need to be replaced depending on use.
I got a great tip from someone who told me to flip it over and use the other side when the first side is worn. No lines but it works.