The gestures work great. It tries to figure out if your thumb is just resting where the button would be or if it is included in a gesture... usually it gets it right, but sometimes it gets confused, which is a bit annoying.
Pinch, zoom, swipe gestures all work great.
The app-switch gesture isn't how I'd set it up... I'd have continued swiping move the highlight in the app switcher, and releasing switch the app. (Instead, the four finger swipe (in either direction) brings up the app switcher with the next app selected. Swiping again dismisses it with no action taken, clicking will switch to the selected app)
The gestures don't work in many apps.
MultiClutch will fix that.
I guess my vote would be above "meh" but below "YES!"