I'm on an iPad 4 and it's not too bad. 8.1.1 is definitely better than 8.0 and 8.1. Although there's still a few juttering here and there, it's very rare.
Thanks. I'm only asking because tomorrow I'll be switching to the iPad Air (v1) and am only keen on upgrading the current software if there will be no lag present. Otherwise I'm more than happy to wait a few weeks or even months for further updates...
I just mean the overall experience, not the occasional hiccup which can happen on any OS. As long as it's not slow in an overall sense then I'm ok with it.