-there is often more room, even at sold out shows because a lot of folks sneak to the floor
-the sound is usually better
-although a little further away, your overall view of the stage is usually better
-you can see much more of the keyboardist/drummer playing... and whole band for that matter but you never see the keyboards/drums like that from the floor
-if there is a light show it's usually better up top
I tend to wonder why most people like the floor over the balcony, especially when I'm up there watching the show.