Gorgeous, entertaining... and free. Holllerrrrrrrr.
The Bellagio always updates the area for the different seasons, and from what I have observed, each time is always different. Every time I've visited, it's been unreal. Giant trees with twisted limbs like out of a Dr. Suess book... orbs of moving water.... bees made out of flowers... massive swans? Not to mention the aroma of fresh flowers that gives your poor nostrils a break from all the cigarette smoke of the casinos. It's beautiful during the day, but if you can stay sober enough to get there in the evening, wait till then... it's absolutely breathtaking.
In my opinion, the Conservatory is a must-see for anyone in Vegas.