Mitch didn't quite have a plain delivery, his unique phrasing and elocution made it his own. If you retell one of his jokes without his stoner drawl behind it, they're pretty lacking, to be honest. I love the man and all of his albums, but a great deal of who he was as a comedian was based on his persona, which was communicated through his delivery. He seemed almost like a friend, not a guy who you would ask to be best man at your wedding, but you would call him up and go shoot the shit with him for a while.

There was a hidden brilliance behind many of his jokes that hints towards an intelligence lurking beneath the "burnout" facade, which is why I think his bits continuously stand up to the test of time. Of course it's hard not to say now that Mitch was a comedic genius, but I personally probably wouldn't have given his act the necessary multiple listens to really appreciate it had it not been the reinforcement of friends and others who already liked him.

As for Dane Cook, I feel like his explosion onto the pop comedy scene combined with the subsequent shunning by the comic community was what lead to the negative attitude so many people use about him now. He did a great interview with Marc Maron where he talks about how the Speak 'n' Spell bit catapulted him out of obscurity overnight and into selling out arenas across the country within the year. He's a tightly wound guy, as evidenced by his kinetic stage presence. I think the pressure of having to live up to his newfound reputation wore him a bit too thin, and that in turn lead many in the comedy world to deride him as he wasn't putting out similar quality material. He is a decent comic with real talent, I think he would have built up quite a following by now if he had ended up going a more traditional route.

tl;dr: Listening to multiple comedy podcasts at work every day has made me way more versed in comedy analysis than is probably healthy. I need help.