I've just returned from a LHR-YYC trip in economy. On both sectors I was impressed by the service. The check in was easy both ends (online check in at LHR, just bag drop), although both agents suggested a change of seating to what they suggested were better options (on the return leg, the agent sat me on one end of the four centre seats, and my brother at the other end in an attempt to reserve the whole row. It worked).
Food was good, and the ice cream on both flights was a welcome surprise. The pitch was average, but I'm sure the seats are thin compared to other airlines, because there seemed to be a lot of legroom. Possibly the most legroom I've experienced in economy. Drinks services were frequent, cabin crew friendly and chatty.
I'd certainly use them again.