Considering I'm now someone relying on this accessibility and usability stuff I can tell you right now it's all a crock of crap unless you're completely blind. For us partially sighted people the accessibility is frustrating as hell.
RWD sites are the best as panning zoomed pages back and forth is seriously sucky.
The software that reads the pages sucks too.
Just hope none of you ever need it as it all needs a LOT of work.
Slightly off topic but there are no guidelines for apps and the magnifier in some versions of Android may or may not be in the phones or could be a vendor supplied or disabled thing. All I know is I'm screwed with a Samsung Galaxy S2 yet to get the latest updates and it's barely usable. Windows 8 isn't much better with only minor accessibility improvements over Win 7.