you should do some research then. for a blind person, IOS7 is unusable. while recent samsungs are almost fine... though i hate pretty much everything samsung did with android, the accessibility stuff was ok.
There are tons of blind and vision-impaired users using iOS 7 and a quick web search shows articles praising the improvements for those users. No doubt there are vision-impaired users who don't like it, too, but it's silly to make a blanket statement that it's unusable.