Most widely used are American dollars and Mexican pesos. Both are accepted almost everywhere.

We wanted to take pesos, but changing money at our bank presented too much of a hassle. No one turned down our US dollars though. Now that I know the routine at the bank, I will start earlier next year and get pesos.

AS for the room, we spent about a half an hour in the room in the morning, getting ready to go out. We were in the room at about 4 for showers and then out again until 11. So for us, an upgrade would have been silly.

Another fellow said that in the summer, you can only be on the beach for an hour or two in the morning, then you go back to the room until after lunch, then out again when it is cooler. The forum will likely comment on whether that is accurate.

We went to the Del Mar last August, and it was extremely hot and humid. But we like the heat, so it didn't bother us. We prefer to sleep in a little, leave the room around 9:30 or 10am and then head back to the room around 4:30 or 5 and take a nap (sleep off some of those mojitos :)) then get up and shower for a late dinner. So mostly we used the room to sleep and for fun... but didn't spend a lot of time in our room. The upgrade would be a personal decision. We are not too picky so the room wasn't that big of a deal to us- I know they are all nice- especially at the Maya.

Have a great trip!