UPDATE: Just updated my beta, and tabs UI looks rather ugly IMHO. Bigger elements than older design, more bulky. Sharp rectangular shapes of each tab UI element are also very standing out. It looks like a touchscreen UI to me.

It also completely disabled all common add-ons like Adblock Plus and Stylish. That's a BIG problem. Looks like Adblock Plus has a compatible beta version at least.

It does feel much snapper though.