Here's a long-term perspective on the Func mousepads: My friend has had one for about two years with the MS Intellimouse Optical and the surface is actually rubbed away. On the rough side there's a huge smooth patch that doesn't glide very well. The same with the smooth side.
I have used an Icemat for two years, and it is by far the smoothest, most accurate mousepad I've ever used, even after two years. I compared it between the Func and I liked the smoothness of the Icemat hands down. With teflon footies on the mouse it glides effortlessly across the pad.