I spent an afternoon at Treehouse, mostly at the beach restaurant/bar, and here are my impressions:

The staff do seem very nice. It was a busy place. Not just with guests but with a lot of beach traffic RIGHT on the break of the water, as the either the beach had eroded or it was very high tide .... The pizza on this visit was not as good as I had hoped -- two months earlier, I had a slice or two with friends and it was great -- and it took a while to get my food (45 minutes or so, par for the course in Negril) ... I did have a quick sneak into the pool, and it was NICE ... Jacuzzi not hot enough.

I did visit a second time later in the week, but if I recall it was merely to dodge a higgler!

Overall, it's a nice place. I know Negriloholic likes it, and her taste is impeccable.