The Sport skin is Lycra, and the tech skin is a thin neoprene. The suit with the Sport skin is lighter and dries faster, and you don't have to be concerned with water trapped between the skin and the bag. The Sport skin will not support pockets with some assertive DIY action.
I wondered about the durability of the suit in general, and the Sport skin in specific, when I bought mine. But two years and a bunch of cave diving (and other diving) later, I have one small hole in the Lycra by my knee, not far from my p-valve, and for all I know, I caused that making the p-valve hole. I'm amazed, actually, at how well the Lycra has held up, even where my harness runs over my shoulders.
I use X-shorts to get around the pocket issue. They work well and most people don't notice I have them on. The only time they cause a problem is on the rare occasion when I forget them. (It's always better to have everything you need permanently hooked together, because in my experience, anything that CAN be left at home eventually WILL be.)