Lovely, whimsical, and free. Also very, very crowded. You can put a positive spin on this by observing that a bunch of total strangers will remain in your memory forever because they got in your pictures by mistake. And you're in theirs.
Sit in the cafe next to the Conservatory if you want to look for more than a few minutes.
Applause to the Bellagio for designing something beautiful for the sake of beauty. Combined with the riot of Dale Chihuly glass flowers in the adjacent lobby's ceiling, the Conservatory is a oasis in a desert of commercial madness.