A decent guide:
http://a.deveria.com/caniuse/
Absolutely, however the aforementioned ambiguity was identified before development of Mozilla’s implementation began (if that was what you were referring to), although Mozilla may have actually been the ones to trigger the discussion of the issue.
Also, I was writing primarily from the perspective of authors who chose to adopt such a feature so early on in its development, and the additional cognitive overhead associated with maintaining and updating such varied implementations - namely property name differences. Mind you, the option to use regular curves only was better than nothing 
Truth be told, isn’t that overhead a part of the cost of being an early (beta) adopter?
cheers,
gary
Indeed