The first question that I always want answered when learning of a new font is how much of Unicode it covers. It a question rarely answered by "We have made a new font." blurbs, though.

Yes, yes; it's aesthetically pleasing, satisfies some set of geometric rules that you say fonts should satisfy, and smells of fresh lemons or whatever. But I want to know what happens when I put a diacritic on that letter "a". Is my system going to fall back to a different font?

Given that there are WGL4 and Unicode variants of Arial, it is a particularly apposite unanswered question here.