We'll have more to say about Android Lollipop in the coming days and weeks, but for now suffice to say it looks great on the Nexus 6. I'm especially happy with the new multitasking and notification options — they're really a lot more clever than you might expect. It also runs fast on this device. Even face unlock seems to work better than it used to, thanks to some software trick that has it running in the background while you look at your notifications.
Google's also added other small touches like a feature that redacts certain information from incoming notifications that may include sensitive items, so that someone won't get the whole story if they glance at your phone. Another feature uses NFC pairing and then Bluetooth to let you transfer the entirety of your old Android device into your new one while they sit side by side. One other hardware trick is Turbo Charging, which will get a nearly dead battery back up to 6 hours of life with 15 minutes of charging at an increasingly higher voltage.