I'm a die hard lifelong Packers fan reporting in as requested:
I sincerely believe Mike Sherman is a very average Head Coach in the NFL and was a fairly mediocre HC in the playoffs. He did improve upon his first playoff coaching experience which was the debacle in St Louis where he and his coaches devised a 3 DL/8 DB lineup to combat the Rams passing attack. After getting blown out, thankfully he never tried that defense again.
Mike Sherman is an exceptionally good person, a high character guy. He would be great for the community of Buffalo. He would do charity work in Buffalo, he would demand good character from his players and coaches (and would generally get it). Team chemistry is big with him. I'd invite him to my parent's house for dinner, I'd trust him around my wife, and I'm thrilled that he is no longer coaching the Packers.
The guy is loyal to a fault. And I mean that literally. Despite his good friend Tom Rossley being an extremely predictable and occasionally inept (imho) Offensive Coordinator, Sherman stuck with him. Despite some of his favorite players (such as Robert Ferguson or Cletidus Hunt) not playing up to their potential, he stuck with them. He never held Brett Favre accountable when Favre continually threw passes up for grabs en route to a 29 INT season.
Just pray he never becomes your GM. In my opinion he was one of the worst GM's in football in the last 10 years. He traded up in the 3rd round to draft the worst punter in the NFL (!), he gave multi-million dollar contracts to loafers like Hunt. He passed on Chris Chambers to draft Robert Ferguson (actually that was technically Ron Wolf's pick in Wolf's last year as GM, but it has been acknowledged that it was Sherman's pick). He traded away literally a dozen draft picks to move up in the draft 7 or 8 times in 4 years, thus gutting the teams' depth. He traded up for Hunter Hillenmayer, then cut him after 3 weeks of training camp because someone else was supposedly a better special teams player, and Hillenmayer ended up starting at LB for the Bears. To his credit he did hit on a few good draft picks such as Javon Walker and Nick Barnett
Sherman is very good at game preparation, and is somewhat innovative in devising offensive schemes. I think he is actually above average in calling plays. (Why he stuck with Rossley calling plays, I'll never know, but the Packers O was better when Sherman was calling plays). He is EXTREMELY organized. Most players love him, but some of his former players like Mike McKenzie hate him...
The worst aspects of Sherman's coaching is in-game. He is very poor at clock management. He coaches not to lose, instead of coaching to win (Witness his not going for it on 4th and 1 in the 4th Quarter of a playoff game vs the Eagles when the Packers had 'em on the ropes and the Eagles couldn't stop the run...I think he lost some of the team after that game)
I think, like Bill Bellichek, he has the potential to be much more successful his 2nd time around as a HC, but I kinda doubt it. Hope and pray he doesn't bring Tom Rossley with him, and keep him far away from the NFL draft. It is a legit concern to call into question his player evaluation skills...
I think, at best, he is more like a Marty Shottenheimer, a good solid coach who can't win the big one
One thing is for sure, he is the guy least likely to be on the TV news for being caught with 2 hookers and a snootful of blow, that ain't gonna happen