Half of me could give the 501 a 4star rating. The other half would give it a 2star at best. For me it completely depends on what time of day you take it.
At 4 in the morning, it's the best thing in the world. A Blue Night route, it comes every 1/2 hour and is always on time. It gets me right downtown in 15 minutes tops. No traffic of course. You'd expect the streetie to be pretty empty at that time, but surprisingly, someone gets on at almost every stop.
Now, when i'm coming home it's another story entirely. At 4 or 5 pm? Forget it! I'd rather take the subway all the way around and a bus south to Queen again. I usually can't even smash myself into the first one that screeches by, it's so packed. Even when i catch it between 1 and 2pm the traffic is ridiculous, the streetcars are sporadically timed and i'm lucky if i get a seat. Plus my commute time is at least doubled to 30 or 40mins.