The bad: In giving up Setoguchi the Sharks lose a player who can, at times, look brilliant offensively. Setoguchi has been an inconsistent but valuable scorer for a while now, and it remains to be seen if there is someone else who can take his place. Charlie Coyle is nothing but potential, for now, but if he turns out to be really good then this deal will be a lot worse retroactively.
The good: Brent Burns! He's good! He's big and fast and scores a bunch and was an All-Star and once beat up Corey Perry. He's a player that it would have been great to have against Vancouver during the playoffs, with all their talent up front running circles around the tired San Jose defense. Burns is used to playing big minutes for Minnesota, so Dan Boyle will finally get some time to catch his breath during big games.
Burns and Boyle as a pairing will make for a crazy power-play, but for even-strength it will probably be better to split them up and pair them with more stay-at-home guys. So not only will opposing teams have to worry about Thornton, Heatley, Marleau, Couture, etc., but they'll have to keep an eye on All-Star offensive-minded defensemen on two different pairings. This is all very good.
The bad: Burns is only signed for one more season, and if for some reason the Sharks can't resign him then this trade will turn out to be a big bummer. He's had some concussion problems in the past two, and his agent fought with Minnesota management about his medical treatment, so those things might become issues at some point.
The bottom line: Brent Burns owns like a million snakes and other crazy reptiles. For that fact alone I am happy to have him on the team.
Here's a video of Brent Burns showing off his pets, which includes him saying the line "These are some of my favorite balls." He's talking about ball pythons, but still.