Having dealt with bugs for the last 30 years of my life I have to ignore these surveys. People with problems are always on the look out for other people with problems and what you find is one irritating bug with a workaround turns into "the whole product is crap" and "this versions sucks". Sure there are bugs, but there are bugs in all products. Unless you're on the other side of the fence it's difficult to quantify these.
But anyway, if you have a problem with an apple product, tell them rather than ********ing on Twitter:
https://www.apple.com/feedback/
They fixed the three I submitted within 2 minor releases (one issue with reminders and one issue with notes)
Compare that to Microsoft who I held a bug open for 9 years via very expensive paid enterprise support on Connect that impacted 50,000. users and they never fixed it. The bug was only closed when they shut Connect down and deprecated Internet Explorer.