Surgical is pretty good if you run a lot of them. When I was trying it out in my sideboard, I felt that I needed to draw it early on in the game, and consistently throughout the game in order to really control the game. It sucks when you draw Surgical after all of their Vengevines, Narcomoebas (if against Dredge), etc. are already in play. But you effectively take away one of their game plans (the one you dislike the most) if you have it in your opening hand or draw it turn 1 or 2.
The decks you're going to use Surgical against usually don't have as many Mental Missteps in hand as a blue deck would, even if they run 4. I tried including 4 Surgicals + 2 Extirpates in my sideboard (taking all other graveyard hate out) one day for shits and giggles, but they could completely destroy their graveyard, library and hand. Also, Surgicals aren't that bad against topdeck aggro decks like WEldrazi, as long as you have some removal.
