We were just at Mr. Sancho's last Friday. I did see Jet Ski's or Wave Runners as you are calling them. This beach is beautiful and a $14 taxi ride from the new Puerta Maya Carnival/Princess pier. Chankaanab is before this so probably a $10-12 ride. This is per taxi not per person each way. There is no fee at Mr. Sancho's. There are restrooms, a double in water trampoline, a huge jacuzzi, bar and restaurant service right on the beach and vendors sell great souvenirs at bargain prices. If you must snorkle or want a Dolphin experience, then Chankaanab would be the best bet.
My husband didn't want to leave Mr. Sancho's as it was so relaxing and the water was so beautiful.