I'm suffering, I think, from lack of RAM on my iPad 5 with iOS 10 now. I've noticed that voice dictation doesn't work anymore if I have several apps running and try to use it in Safari. If I reboot the machine then I can get it to work. This isn't a very scientific test.
Mrs Weaver has an iPad 6 which I think has 2 GB. Whereas my iPad 5 only has 1 GB. Her machine feels a lot smoother than mine at times, and she has had no complaints about iOS 10.
Since I ‘upgraded’ to iOS 10, which I regret as a hasty move, my machine seems to stick at times, typing into a multi line edit box in Safari is sometimes slow or even becomes unresponsive for several seconds at a time. I did read some early reviews but it seems they were overly rosy and not sufficiently thorough.
I'd quite like an iPad Pro larger screen version which has 4 GB, I think, but I'm too mean to pay the current silly prices, so I'm going to wait and see what the next model looks like first, before I decide.