Clarification on TRIM, 4.3 and Nexus 7 (2012) Please?

Hi Verge community,

Can anybody care to clarify the addition of TRIM and Android 4.3 in regards to the 2012 Nexus 7? What's the deal with needing to have the batter above/below 70%? And do I need to always have it in that range?

I also factory reset my tablet yesterday and today there's still some lag here and there, like in the keyboard when I type and just overall scrolling and navigating the interface; does it take a few days for the smoothness that everyone is raving about to kick in?

I bought the updated 7 but I would like to see if everything can go back to butter and usable with last year's tablet, so any tips/advice on this would be greatly appreciated. $230 back in my pocket wouldn't be a bad thing.

Also, anybody else still using their 2012 7 with good experience and feel no need to upgrade?

Thanks, guys!