I've been thrilled with mine. I use MMF 95% of the time, and Fondx the other and have no problems. I seasoned it with Crisco the first time I used it. One time I didn't have my consistency right with MMF and it very slightly stuck to the Mat. I washed the Mat off in my sink with my sprayer, very hot water, and some Dawn, just rubbing it down to make sure it felt completely smooth with no trace of fondant left, then reseasoned and never had another problem again.
Another thing, I rarely let my MMF sit overnight. In fact, it's usually even slightly warm still when I use it. Without the Mat it's so stretchy and soft it's hard to use, but with the Mat it's perfect to smooth over the cake. Just a different perspective.