I ride frequently and it really varies by which train you're on. Some are smooth, others seem to have an issue that makes them rattle constantly. I know a week or so ago they actually had singes in the stations telling riders that several cars were undergoing repairs and wait times may be longer than usual. Hopefully the were fixing the rough riding.

By contract, on my trip to Toronto I was surprised by how much smoother their streetcars are than the Q Line! Even the smoothest ride I've had on the Q is rough compared to what TTC is rolling.