Wanting advice on staying in Tulum or Akumel (2 adults and a 12 year old). Which place do you recommend as a base for exploring the area for 4 nights prior to spending time in PDC? Or would it be good to stay a couple of nights in each area? Accommodation ideas for all areas greatly appreciated (condos or bungalows on beach-no ALs). Thanks!

For condo's in Akumal, try googling locogringo.com and you'll get good advice.

Tulum is mostly small cabana hotels with an eco-conscience, so if a/c is important, you will want to stay in Akumal or one of 3 hotels in Tulum that have generators: Ana y Jose, Los Lirios or Parayso.

Tulum and Akumal are quite different, so it depends on what you want.
Akumal is a quiet community of small condos and a few hotels lining the beach. The beaches are somewhat protected and great for snorkeling. There are a handful of good restaurants, and Akumal seems to attract mostly American families.
Tulum is made up of two areas - the beachfront, which is lined with small, mostly cabana type hotels which generate their own power;and a few miles inland is the actual town, which is a small Mexican pueblo with a few restaurants and shops. The beach at Tulum is miles and miles of wide open, white sand, and the surf can get a little rough at times. There are some stretches of beach that can be nearly deserted. Tulum seems to attract more singles, Europeans, and the tie dyed set.
The two towns are about 1/2 hour apart, so you can easily stay at one and visit the other. I wouldn't split my lodging between the two. Staying a few nights in PDC will make a nice contrast to either Akumal or Tulum. We always do a few nights in PDC, then a few nights in either Akumal or Tulum (we love them all!)

Thank-you for the advice everyone! It's a tough call. I am leaning towards Tulum, but wonder about the lack of AC at the end of May (I think it gets pretty hot at this time..with rainshowers?) I will look into the places you recommended 'pepper131'. I'm sure I can't go wrong in either place! Beats the 'wet coast' of British Columbia! Zootsi-where do you stay in Tulum and Akumal?

In Akumal we always stay at Vista del Mar, a small hotel directly on Half Moon Bay, with private balconies and terraces. This is a clean, comfortable small hotel that runs about $100 a night. Half Moon Bay is a great snorkelling spot, but the bottom is all coral and rocks, so to actually swim, we walk (15 minutes) down to the beach at Akumal Bay. Right next door is the Buena Vida restaurant, our favorite eatery in the entire area.
In Tulum, we have stayed at Tierras del Sol, a small grouping of cement and bamboo cabins right on the beach. This year we are going to try Los Lirios, which also looks nice. If you are in downtown Tulum, try eating at Don Cafetos if you want the real Mexican experience.