I've been cutting materials about 1/8th of an inch thick with this blade. I find I have to use to multicut function to make sure there aren't any little spots that didn't get cut completely though. I also have found that the thicker materials need a little extra sticky to stay in place on the mat (makes sense, since you're cutting through more material at a time there will be more resistance). I just use some double sided sticky tape, and it works just fine.
On a side note, it fits in the Cricut Cake machine, so if you just get the sticky mats you can use it to cut out papers/leather/foam board, whatever, instead of just cutting food items. I know Provo Craft says not to use the Cricut Cake for non food items, but they are full of crap. If you use a separate mat and blade, then NONE of your machine will come in contact with both your food items and your paper items. Besides, even if you used the same mats/blade, if you are making things out of paper that is SO toxic that a microscopic sliver or the residue of the dye could make you sick then maybe you should reconsider operating the machine in your house! I'm pretty sure anything that toxic would have to carry a warning label anyway... So as long as you aren't flavoring your coffee with scrapbooking glue, I sure you'll be fine. Provo Craft just stands to make MUCH more cash if you buy both a machine for both food items and paper products, so of course they'll say you shouldn't use it for both.