I'll say a slow death by multiple swords (they use more then just 1, because the leave the sword in the bull after a stab) is way more painful than a knockout by a hammer and executed while the bull is unconscious. So can't say it's the same.
But then again nature are equal brutal anyway.
I am a little on the fence about bullfighting. On one side i can see why it isn't a big deal if the bull gets eating after the show, but on the other side we humans should know better than to be so barbaric.