Neither charming nor genteel, the 501 isn't even the equivalent of the 506.
Traversing the already busy Queen St corridor, I think this unfortunate vessel adds to rather than lessens the congestion. Taking it westbound one Saturday afternoon, it wasn't too awful but it was very crowded. However, on the return trip eastbound, it took forever to arrive and then when it did, it was slow as molasses on a January morning in Cottage Country (which is to say it was very slow).
I exited at Spadina and walked to my hotel at University and actually beat the streetcar. Granted, I'm a already brisk walker and I really had to use the restroom so I was walking extra-fast to get to my hotel but still, when walking is faster than riding, you know something is just not right.