I can't believe people get bothered by this. Actually, when the Leafs had Joe Bowen on TV and he was a homer I enjoyed watching games more, to be completely honest.
I understand Bowen is a Leafs fan and homer, but the majority of announcers favour their team. That is why you have a home AND away feed.
As for Edwards, he goes beyond being a Bruins fan to let it take away from the quality of his broadcast IMO.
For example, last year in the playoffs he got pissed that play was stopped because a Leaf player took a puck from a hard shot to the face and exclaimed something like, "That is unbelievable. I get it if a bone is sticking out of your leg, but come on!" while a guy was down on the ice. He didnt complain the next game when the same thing happened to a Bruins player.
I get being a fan and how it can be annoying for the opposing fanbase to listen to that stream (Bowen and some others), but at least they are good quality broadcasters that don't make fun of the other teams or talk shit while the opposing players are down on the ice/potentially injured (to my knowledge).
Edwards also routinely cheers whenever a Bruins player does an illegal hit or boarding.
If Edwards just cheered foe the Bruins, got excited when they were doing well, and talked more about their team than the opposition then I would have him as one of the better announcers.