We stayed for a week in August 2010. It was very peaceful and serene. One nice thing about that time of year is all the rainfall really "greens" things up.
I would highly recommend THV, as long as your have a car, as the bus system is very inefficient.
An August thunderstorm in the Treehouse Villas is the closest our family will probably ever get to a real rainforest!
We never had any problems with bugs, but didn't spend much time outside other than at the pool.
http://i61.tinypic.com/2mfyebl.jpg