We purchased a timeshare and the extra golf package, and have always been told "all resorts are full" and have never been able to use even one day. But, if you look at their resort sites or Travelocity, rooms are plentiful! They would rather rent them out to the public and tell you no weeks are available.
Puerto Vallarta. It is a beautiful place with mainly nice people. There is a variety of things to do. There are other timeshare promoters who are worse than the one described... DON'T buy a timeshare in Mexico. DO buy one through private sellers here in the USA... much much cheaper!
Villa Del Palmar has always had space available when we called. Many of our friends purchased units there. We also liked Rancho Banderas... very low sales pressure there to buy... very quiet place. The only thing we did not like is the distance from town---- quite far.