We flew three times with WestJet while in Canada and something went wrong with every single flight.
We are from Australia and I would say that it's fairly well aligned with our budget air offering here - Jetstar. They do have pretty cheap fares and a fairly wide offering as far as flight destinations go but they aren't the most reliable and I DEFINITELY wouldn't book with them if I was depending on a time sensitive service.
Our first flight from Vancouver to Calgary was the least eventful. Nothing major but flight was delayed about an hour due to some kind of mystery medical emergency.
Second flight was an unmitigated disaster. We arrived early for our flight from Calgary to Kelowna. Unfortunately it was cancelled due to "unexpected maintenance" AFTER we had passed security. By the time we made it back through security the people who had arrived after us seemed to have taken most of the rebooking slots on the next available flights.
They eventually booked us on another flight the next day. We had tickets for an event the next day and were looking to lose a few thousand dollars if we missed it so we were pretty upset and, after desperately calling customer service (who were great) they managed to get us the final seats on the last flight out for the night. We still had around an 11 hour wait at the airport with two kids which wasn't ideal. I noted that there were a lot of unhappy people milling around the airport as our flight wasn't the only one cancelled.
Upon arrival in Kelowna we couldn't actually disembark as there was a further issue with the ramp so were also kept on the plane for around an hour.
Third flight was from Kelowna to Vancouver. This one the delay was on the runway. itself. We were all boarded and then ended up sitting there for an hour as they were unable to take off due to a "passenger allocation" issue.
Staff overall were lovely and pricing was fair. Due to the lack of reliability I'd be hesitant to recommend though. They definitely seem to have more than their fair share of issues.