I have the C4. I was using an XTrac Hybrid, and the C4 is definitely more slick. It is a thin pad which does wrinkle (permanently) easily, but this should not be an issue unless you intentionally abuse it.
Durability is excellent- have been using mine heavily for about half a year with no signs of wear whatsoever.
I should mention that I use an optical mouse with teflon mouse tape. I belive that the company that makes the C4 sells mouse tape by the roll. One roll should last you a lifetime easily. I have no idea how well it would work without tape.
Overall, I am happy with the pad. It is worth mentioning that if you sweat a lot, you will need to wipe it down constantly.
Edit: The C4 is much, much slicker than even the slick side of the 1030, from my personal experience.