If you are on 9.1.x, stay there as long as possible. I never had an issue and was able to upgrade my way through the 9.1.x line without a blip. I would avoid 10.1.x like the plague, it has just been one disaster after another. We are hoping that when 10.1.11 finally become preferred, it will be the answer to our prayers, because so far it has been a straight nightmare.
Your experience may be different, I'm just telling you mine.