Is there some reason to expect one to be faster than the other? Each is essentially JavaScript plus vector graphics. Some particular implementations might suck

Is there some reason to expect one to be faster than the other? Each is essentially JavaScript plus vector graphics. Some particular implementations might suck more than others but they are ultimately the same sort of technology. If anything, I would think that Flash has the potential to be faster since it was designed from the beginning to do only what it does, whereas <canvas> is an extension to the already massively complicated technology blob that is HTML.