Ditto on the public transportation, you will find tons of relevant info at the PV forum on tripadvisor.com.
We just stayed in the Romantic Zone at Casa Isabel followed by a second week at Dreams and would highly recommend that over the hotel zone. You can walk and enjoy the old town, whereas if staying in the hotel zone you are separated from this experience.
Don't miss the Rhythms of the Night excursion.

"Travel changes you. As you move through this life and this world you change things slightly, you leave marks behind, however small. And in return, life — and travel — leaves marks on you.”
-Anthony Bourdain