My main concerns are mostly on the UI. I love 70% of the UI changes, but some are weird and frankly, ugly
THE UGLY
1) The navigation bar. It looks childish and isn't informative. The current navigation bar is perfect IMO.
2) The notification shade. If you guys head over to YouTube and search for,"Android L Hands on", there's a video showing the notification shade in action. It looks disorganixrd . Again, the current notification shade looks better. All they need to do is add connectivity shortcuts at the top and change the font and pallet here and there.
THE "REMAINS-TO-BE-SEEN"
1) The redesigned multitasking interface. Now, you have to scroll through a carousel to jump to the previous app and if you have multiple chrome tabs open, there's more scrolling. I won't say the current style is perfect, but it seems to be more intuitive.
2) The animations. Sure some are really eye-pleasing but there seems to be a little to much; especially the ripple effect on button presses.
3) The actionable lockscreen notifications. Again, I feel that it could have been done better. Google should take a page from 3rd party apps like 'DynamicNotifications' and 'Peek'. To early to give judgment, so we'll see how it pans out.
THE GOOD
1) Project Volta. Stock now comes with battery saver mode. A little late to the action, but a welcome addition.
2) ART as default. Expected, but still a nice change.
2) The rest of the UI elements. E.g. Gmail, Gallery, Settings.
That's just my opinion. Its not final since I've yet to use it
