Vexilogically, it's terrible. Too much detail, no interesting or bold patterns. From a practical standpoint, it's barely distinguishable from about 20 other state flags, all of which are blue with some kind of crest in the middle. If we ever went to war with New York or Michigan nobody would know who was on whose side.

For comparison, see Arizona, Texas, Colarado, New Mexico, Alaska, or Maryland's flags, which are actually used by normal people as state pride, and are even popular as tourist souvenirs. SC or Ohio are also pretty good IMO. State seal on blue background is pretty F-tier.