Anime News Network gives the art an "A": http://www.animenewsnetwork.com/review/puella-magi-madoka-magica
Cloaked does NOT think it is worthy of an A.
This would not be such a problem had they not given Heaven's Lost Property (Sora no Otoshimono) a "B": http://www.animenewsnetwork.com/review/heaven-lost-property/blu-ray+dvd-season-1
THE ART IN SORA OTO IS LIKE, A BILLION TIMES BETTER.
Puella Magi Madoka Magica screenshots:
Heaven's Lost Property screenshots:
Cloaked used her decisive skills as a rogue to deduce which series had better art. Cloaked is sure other seasoned rogues can do the same.
DISCLAIMER: Cloaked knows PMMM is all super-good and whatnot, but it is definitely looking like the producers settled with the art and didn't give it as much as they did the plot.
Who knows? Maybe Cloaked is wrong.