Had two days in Puerto Vallarta - granted we are sorry we missed Mazatalan, but did enjoy our time in PV. Our first day - the husband played golf at the Flamingo and he really enjoyed it. The course was beautiful and well maintained. It was built around a bird sanctuary and had a wide variety of flowers and wildlife (including crocodiles). I took a tour of the city with the Cathedral as a highlight, as well as a cooking class at a local restaurant and really enjoyed the experience. The Malecon is a great place to go and walk, take photos and take in some of the local color. The only thing that got irritating were the street vendors that could not take no for an answer. The second day we did not go into PV proper, but went in the other direction and visited a tequila factory. This was very informative and we really enjoyed it.
One thing - the city of PV is very poor when you get away from the main "tourist" drag. It is also a very dirty town, except on the area around the Malecon.
The other thing that disappointed me was that right next to the dock was WAL-MART/Sam's Club. The other was a taxi driver who got lost then tried to charge an inflated price over what was told to us originally. Be very careful when dealing with them.