I recently got my Grassy Plains matt from Frontline Gaming in the mail, and it is absolutely beautiful. The mat itself is very thin, but has a rubbery underside to prevent it from sliding around on the table. Its also decently heavy, so there is virtually no risk that someone is going to accidentally catch the edge of the mat on a belt buckle or whatever and smash the contents of the table across the floor.
I only have 2 bad things to say about them:
1. Shipping is a b*tch!
It cost me about $100 for the mat itself and then $70 to get it shipped to Perth!
2. Mine arrived with a couple of creases in it, and I have yet to figure out how to remove them. I havent yet worked out if these things are iron-safe, and I dont want to test it by taking a hot iron to my $170 mat!