I just did a factory reset, and it's like an entirely new device!
I was having multiple issues, from extremely laggy performance, wi-fi dropouts, sync issues with Google calendar (all my data would just randomly disappear), extreme delay when pressing power button, mostly everything that's been mentioned.
So I backed up as much data as I could, and took the plunge. And a refreshing plunge it was!
The phone now operates so much better and so much smoother! No lags whatsoever. I am still in the process of re-installing some apps, but from what I've got done so far it was worth it.
So bottom line, if you're unhappy with your Note II after the 4.3 upgrade, go ahead and bite the bullet, and do a factory reset. Make sure you back up your data first, 'cause it won't be there waiting for you.
Posted via Android Central App