I'm on a full week of using my N9 now with the Keyboard Folio. If using the Keyboard my battery drains within 7-9 hours of use (Gmail, Web & Skype + G Sheets only). Without the keyboard I have gotten 16 hours.
2 days ago I started noticing that Apps are taking time to open, switch between apps and close. No idea why this happened all of the sudden, but nothing I do speeds things back up. Hopefully the Android 5.0.1 update will resolve this, although it is strange that the device just randomly slows down.
Few others:
When downloading PDF's in Chrome and the download completes, the Notification and symbol in the upper left will constantly flicker, as if it's having troubles "completing" the download
There are times I will login to the device and it will immediately turn the screen back off. I've had to force turn off the device a couple of times to correct this. It happens 1x a day for the past 3-4 days.