I paid for wifi for everyday and never had a problem in room or out. I never needed to download anything big or fancy, just wanted my iPhone and access to emails etc...
I found the wifi was great near the reception area. I was able to log into servers back home and put out a few fires, I was very impressed. It was not as great from the rooms. I am not sure how much success you would have connecting your blackberry to the wifi however, if I remember correctly it was session oriented and required you to log in through your browser so it might not connect with a Blackberry, though I did not try
We just got back and I paid for wifi on Tuesday and had it till Thursday and then paid for it Friday morning and had it Friday thru Sunday am. So I kept getting a day free, i wouldn't go back and pay for another day until it finally told me i was expired. it worked great at the pools and the beach and restaurants but did not work at all in our room. Was it worth it, ehhhhh.
welll few years ago i was in cancun i bought blackberry thru sprint with me and it works !!! i have data plan and didnt have different plan just for cancun trip... the blackberry instant messaging works like u r in america so i am planning on asking sprint to activite when i go to cancun this april 13th just to make sure