I've been using these shorts while paddling a surfski for about two years. I use them all summer, but use the longer pant version in the late fall and early spring. As a surfskier, I'm always sitting in a pool of water. The 0.5mm neoprene of this product helps preclude me from feeling cold. It seems to be relatively smooth on the outside, not precluding good rotation.
On the inside, though, I've had some issues. I find that, when rotating, the inside of the shorts sometimes rub me raw on my back-side (i.e., rubs the skin completely off). This is uncomfortable, to say the least. I try to prevent it by using tape across my backside, inside the shorts. I don't know if this is a problem with this particular fabric, or if it would happen with just about any fabric -- just don't know.
Overall, I'm pretty happy with these. Though as I said, for colder conditions, more coverage would be desirable. If I lived in FL or some other warm climate (I don't -- I live in MI), I might use something like the McNie Kayak Short -- or perhaps a longer pant tights of some sort.