he isn't a good gameday coach but considering how small scouting staff bengals have and they don't use any independent scouting services (only NFL team not to?), barely sign any FAs, have cheap owner/GM who is also stupidly stubborn (not trading chad Johnson for two #1s back in '08), they have built some pretty damn good teams.
not sure if the insistence of giving way too many chances for failed high picks comes from marvin or brown. not playing justin smith inside was pretty bad as well but i don't think there are many occurences where their former players start playing lot better after leaving cinci.
Can't find the stat after a quick search, but I read something the other day that said the Bengals have the most picks still playing in the NFL, by a decent margin too. regardless of their scouting situation, over the last 10 years they've done a great job of drafting NFL talent. Also, the "Mike Brown is cheap" narrative is a little dated these days as they've done a really solid job of locking up and/or extending their top end talent.
Hit the nail on the head about Marvin though, he's an awful game day coach and really just not a winner when it counts.
Also, regarding the Bengal's success, i'll take it to my grave that Andy Dalton is criminally underrated. Its easy and obvious to look at his playoff breakdowns, but in my opinion, his biggest fault is not being immune to the Marvin Lewis effect.