Actually, I think cc (without fees) is the best rate available. Usually the current actual market, bank-to-bank, rate. At ATM you may get hit with a conversion fee and something just over market. Downside to use of cc is the MX govt, as far as I know, taps into ALL the bank, PayPal, etc transactions and takes I think 19% tax. Businesses have to account for this in sales pricing. So when dealing with small places or street vendors one might get a better deal using cash/pesos.
Enjoy, most stuff will fell like it's free.
We tried Kool Beach club one time and found it too crowded. Mamitias is about the same. Preferred the smaller places.
As I said in last post, Cannibal Royale at Coco Beach is a nice place for lounging. From just past there and north is a long (hopefully walk-able) beach that takes you up to a nice shallow cove good for wading out, lite swimming, etc. IF you like long walks.
Enjoy