I came here to have the battery replaced on my MacBook Pro (13-inch, Early 2011) after reading decent reviews. They are also Apple-certified, which helped to influence my decision.
I brought my laptop in to CSC's temporary pop-up location (just west of the College & Spadina store) around noon, and the work was completed by 5pm the same day. Not the cheapest service, but you get what you pay for -- and the new battery works great.
Apple followed up with a service questionnaire a few days later, which was reassuring. It's nice to know Cupertino has its eyes on its authorized resellers.
Overall, I'd return to have all of my future Apple products serviced -- it beats waiting in line at the Genius Bar any day.