When he was hired, I remember thinking, "this guy won the ***** Pinstripe Bowl!!! We got ourselves a real HC!!!"
Turned out that wasn't really the best litmus test.
In seriousness, Marrone was hired into just about the biggest dumpster fire in the NFL. Inept ownership. Inept front office.
Was he great? No. But when he left, the Bills had a winning record and a top defense. I never blamed him for bailing with all of the uncertainty. I think he did the best job he could being the head coach of a horribly managed team.