They don't feel right. The 'hover' state should be the 'down'(active) state; the hover state looks like button is pushed in. The hover needs some kind of glow or subtle gradient change, then when the button is clicked it needs to look like it's pushed in. It's strange they've done this because the buttons on twitter.com feel correct and get pushed in like real life buttons.
Also the fade animation on the button totally unnecessary, it just animates for the sake of being animated, it doesn't serve a purpose. Animations need to serve a purpose, such as the Mac App store whizzing purchased apps into the dock.
Everything else is pretty fantastic, but those button states make my skin crawl, they're the first thing to get changed if I'm using bootstrap.