We visited both of these ports last year. We did the horseback riding excursion (booked on our own) and the beaches we rode on were littered with trash. The water was still beautiful though. We also rode through a coconut grove and it too was full of litter. And yes - the vendors are very annoying. I bet I said, "No, Gracias" 100 times. It was very irritating. I know that's how the vendors make their living, but the same ones kept coming up to us over and over again.
I can't speak for the PV beaches since we did the canopy tour and never really saw their beaches up close.