The Precision Mousing Surface is a premium mousepad replacement, made by 3M. Its surface is made up of many tiny pyramidical nubs, which are designed to present more friction to the mouse ball while at the same time preventing dust, skin and general crud from sticking to it. The plastic upper surface is mounted on a layer of thin rubber which stops it sliding around the desk.
Unfortunately, the rubber layer isn't very effective. 3M manufactures a spray-on adhesive designed to semi-permanently attach it to your desk, but I've found that Blu-Tack works just as well, especially if you roll it into thin strips before sticking.
The plastic pyramid design is not as effective as the packaging claims in reducing mouse-crud buildup. Also, after sustained usage, the plastic coating on the top that allows your mouse to slide easily is stripped off, resulting in a mouse that requires much more effort to move. A temporary solution to this is to move or rotate the mouse pad so the mouse rests on a non-worn area.
The main problem with the PMS is that it's not a huge improvement over a standard mouse pad. A couple of months after I wrote my original writeup praising my PMS, I got fed up with it and bought an el cheapo fabric-covered mousemat. The new mousemat is thicker, which would be an issue if I were using it on a standard desk or if I were in the habit of frequently running my mouse off the mat. However, since my desk has an integrated wrist rest, and my mouse sensitivity is set high enough that I never move the mouse out of a small area in the centre of the mat. As well as this, the fabric covering on my current mousemat absorbs moisture from sweaty hands much better than the PMS's plastic, which is a pleasant change.
Generally, I would recommend not wasting money on a PMS, unless you particularly like the (admittedly nice) purple-and-black design and sleek look, or if the thickness of traditional mousemats irritates you.