They do have dryers at CN. Decent is a relative term, for me they are ok. I would prefer my own but there is not an outlet in the bathroom so I end up in the room drying my hair and that does not work as well. Of course, with all of the humidity I have pretty much given up trying to get my hair to do anything any.
I use the resort hairdryers and they are just fine. They are the small ones attached to the wall, like most hotels. However, I have very fine, thin hair, so it doesn't take much to dry it. I have a friend with long, thick, curly hair who has to bring her own. But like Blondie said, it's so humid, I just embrace the beach hair and don't spend the time to dry it or flat iron it because the minute you step out of the room, the humidity takes over anyway.
I had long, semi-thick, naturally wavy hair when we went in June, and used the hairdryer there with no problems. I don't know if it was the heat or if my hairdryer at home stinks, but it seemed to dry my hair as good as or even faster than the one I use at home (keeping in mind that I wasn't as stuck on blow-drying it straight with a brush as I am at home, as it was just curling up in the humidity anyway). I was very happy to not have lugged mine with me.