My wife has a N7 2012, with 5.0 thru 5.0.2 it was very sluggish. Facebook, email, games, ... Some crashes.
I had done a factory reset, loaded 5.0 & reloaded all aps after 5.0 OTA install
With the 5.1 update she says it's very good now. Back to how it was before the initial Lollipop update.