Questions on Android multi-user feature

Hi all,

Looking for a bit of advice really.

I bought my parents an Asus transformer 300tf (basically a 10" nexus 7) about a year ago. They love it.

Initially as it came with Android 4.0 it didn't have multi-user support so we set up both of their google accounts to the tablet anyway - which worked ok but led to confusion as they had to remember to check who's gmail/google+ account they were in then log that person out and log in as them. We wanted them each to have their own username (especially now as my Mum as her own android phone).

When 4.2 was available I deleted one of the accounts from the main account (leaving it as my mum's) then made a new user for my Dad and google magically synced everything back.

I'm not there all the time but when I was there last, it felt really slow even my parents noted the performance wasn't like it used to be. (I'm a galaxy nexus user and haven't experienced as much slow down).

I've read that wiping the tablet completely and starting over with users might help - I'm a bit apprehensive to try this although it shoudn't be too bad as nearly all their stuff is on google's servers.

Does anyone have any experience with android slow down (perhaps even related to multi users)?

Thanks in advance

p.s. here's a random gif in case I wasted your time: