Mathworld is much much better in general.
(Somebody's probably going to reply "Wikipedia is an encyclopaedia not a tutorial".)
One of the problems, I think, is that there are competing "views" of linear algebra. Mathematics students are taught a different class than everyone else where vector spaces and linear functions are brought to the fore. Everyone else seems to get a more computation-focused course. So there's a tension there where if you write a math-style article about matrices where this fact about the columns would probably be the definition of a matrix, everyone else might not even recognize what's going on.
There's also the issue that the current article is so sprawling that refactoring it to subject it to a unifying plan would require a large rewrite, and that's hard in an environment like Wikipedia.
It's not the same as a textbook, but generally, after reading the Wikipedia page, I know enough new terminology to intelligently Google for more complete resources like lecture notes, papers, etc..
Wikipdia math pages (and for some sciences too) are correct in the details and yet provide no insight.
It's almost backwards what you want from an encyclopedia, which should be an overview with references to more details.