I use the paper based for risers, but like Jason said it is hard as a rock! I use a new roll of 36 grit in the drumsander to rough it up...never had an issue. It's not real easy to finish sand either, so keep that in mind. After your sealer coat, you will usually see a few sanding marks that were missed...the black shows everything! So plan on sealing it twice.
Also, I DO NOT use it for wedges!! The stuff becomes pretty brittle when cut thin, so I wouldn't trust it in a wedge fade or even as a one piece riser in the fade area.
As far as cutting it, don't use any blades unless you plan on throwing them in the garbage after your done! I use the cheap 10" depot table saw blades and rough cut enough for two risers...after that it's junk.