I really hope iOS 10 turns out a lot more polished than iOS 9 ever was.
I'm not talking about crashing, but rather performance and the overall glitchy interface.
iOS 7 worked great for me... very few glitches... performance was great too.
iOS 8 was glitchier. Had a lot of UI bugs (like title bar changing from big to small to big to small again after unlock)
iOS 9 takes the cake with glitchiness. There are not only UI bugs, but overall performance took a dive (even on devices that shipped with 9.
I hope that iOS 10 is what I've been waiting for, but I'm not holding my breath.
iOS 10 will most likely be even worse than iOS 9, but people will love it because it's Apple.