lake Which hotel/resort should I stay at in Tulum, Playa del Carmen, or Cancun?

I am going to Mexico in November for a friend's wedding. She's getting married in Tulum. She mentioned checking out hotels in Playa del Carmen. And we fly into Cancun. It's going to be a vacation for my girlfriends and myself. Where should I stay, and how much should I figure in for transportation? Would it be a better time staying in Cancun and paying for a cab to Tulum, or vice-versa? I've never been out of the country so all suggestions would be appreciated.there