first the good things about Akumal

It is NOT like Cancun and Playa del Carmen - the beaches are wonderful and there are plenty of places for snorkelling, without having to spend a fortune on theme parks and without party (read drunks) crowd you meet in Cancun or Playa

A few of the restaurants serve really good food and not too overpriced either.

The bad things:

if you have the possibility of staying in a place with a kitchenette, bring EVERYTHING you need from Chedraui or other shopping facilities outside, cause EVERYTHING in Akumals supermarkets is extremely overpriced, sometimes almost three times more expensive than in 'real Mexico'. The ATM machines work sometimes, sometimes not, don't count on it, and they have ridiculous extracharges and 1 dollar will be change at the absurd rate of 11 pesos (instead of 12 .50).

 Try to avoid taking their (overpriced) taxis, even if they show you their 'official' pricelist. you can catch a collectivo to Tulum archeological area for 30 pesos and you can catch a collectivo to Playa del Carmen for 40 pesos (which is still expensive in terms of normal Mexican prices but it is not as outrageous as what the local taxis try to charge.

In other words: enjoy Akumal, the beaches, the snorkelling, the relaxed atmosphere, the food, the nights with the  sound of the waves, just try to avoid the tourist-trap aspect of it, which unfortunately will increase over time.