All my Nexus devices have been updated to Android 5: Lollipop and I’m getting use to the changes.
My old 2012 Nexus 7 was first to be upgraded, about a week after the release of Lollipop. Then a week and half later my Nexus 5 was upgraded. I thought the Nexus 5 would be first honestly.
The Nexus 7 had problems, the upgrade was fine but it got really really slow afterwards. I wiped the cache a few times and that helped but after a day of use, it would go back to super slow. In the end I had to wipe the whole device and just start a fresh. Luckily Google made the process much quicker and easier. Using NFC on my Nexus 5, it sets up an adhoc network and transfers most of the settings across. Only real issue is setting up all the individual apps.
Android 5 is actually really nice, its like the jump from Android 2: GIngerbread to Android 4: Icecream sandwich (we don’t talk about Android 3: Honeycomb). Icecream sandwich’s Halo interface was great and to be honest Material design is a little weird to get use to. But you get use to it and the way it works. In actual fact the interaction design of the interface is well thought out.
I basically think of everything being pieces which are viewed from a top down view. The shadows help with this and the motion makes things very clear. My own gripe is the flat colours but the edge to edge pictures help break things up quite a bit. I would say its not as revolutionary as the Windows Metro interface but its smarter and is a lot clearer.
Quite interesting when you look at the other human interfaces guidelines in software.