Rock (even pea gravel) + Texas sun = burned feet + rocks kicked into the pool
Kool Deck is nice when it is first installed but, honestly speaking, it tends look very shabby in the out years as it degrades and begins to peel and flake. I know lots of people around here that buy homes with pools and rip out the old Kool Deck as soon as they can.
Concrete, when done by a professional that is careful and diligent, looks great and lasts a long time. As long as the installer knows how to grade and prep the sub surface, uses mesh or rebar to reinforce the concrete and knows how to do control joints and mastic expansion joints, then a concrete deck can look as good as any installed hardscape. Stamped concrete is usually the most expensive but it gives you lots of choices for a faux stone look. Acid washing and aggregate exposure can give you a good non-slip surface. Salt finish looks very "antique" and I have lots of salt finished walkways but you need to be careful because it's still a concrete surface with the smooth creme layer intact (unlike acid washing) and so it can get slippery when wet.
