Definitely read the reviews of Cahel Pech here on tripadvisor. They are spot on.
I stayed there myself. You'll see that the reviews for Cahel Pech are very mixed. That's because there are some nice newer cabanas and some dingy older ones. There was only one left by the time I booked and I got a dingy one. It smelled a little bad in the bathroom when we first got there. By the end of our trip, after taking showers every day, it smelled very bad (like we were getting mold wet or something) - so much so the smell from the bathroom extended into the bedroom. We're sure it wasn't us either as did not happen at any other hotels we stayed at.
The location is fantastic (arguably one of the best since you are close to the city and yet you don't get any city noise), the view is wonderful, and the food is good as well as the tours you might book through them. The cabanas actually look very charming. So, if you get a good cabana, you'll probably love it there. If you get a old dingy one, you might be disappointed you stayed there.
Maybe you can try to ask for one of the nicer cabanas or something else that makes sure you get get one of the better rooms.
Edited: 2:32 pm, October 07, 2010