Condra is defensively responsible, that's it. He isn't a "great" defender, but he will do his job on defence. Condra isn't "great" at pk either, but he is good. he knows how to stay in the shooting lane and pressure the puck handler. If Condra manages to take the puck away, he doesn't know what to do with it. He often ends up giving it right back in an attempt to clear the puck, or if he skates it out, ends up shooting the puck into the goalkeepers midsection. He can sometimes forecheck the opponents PP unit aggressively and still get back to defend. Condra is able to help eat up seconds on the clock during the pk, that is his job and he does it well enough.
Stone is also defensively responsible. He just isn't as quick as Condra, but he brings a higher hockey IQ, and better stick.