I have cruised the Mexican Riviera 8 time in the past 3 years and Puerto Vallarta is my favorite Port of Call. Almost always go the "The Blue Chairs" via the local bus which runs from right outside the main gate of the Cruise Ship Terminal. The cost is about .25 cents US as best I can recall. Taxis run about $5 US dollars. I don't take the bus to save money. I just like observing the locals and being a part of their daily lives.
The Blue Chairs is well worth while and the senary is fantastic if you like hot young Mexican Boys and other handsome men from all over the world.
I will be there next Wednesday onboard the Carnival Pride.