I used to think they were the same as proto based on the appearance of the older ones, not too long ago I had to disassemble a large number of rusty, seized 3/4 bolts. I wore a few cheapo wrenches out in short order to the point where the bolt would spin almost as soon as the trigger on the impact was pulled. I then tried a challenger, it lasted significantly longer but eventually gave up as well. At this point I was down to better wrenches I really didn't want to unnecessarily abuse in this manor, but I did have one proto 3/4" wrench that had been modified with a bend for a one time job. It easily finished the project, well over half the total fasteners, with much less visible wear. There was a difference.
Don't get me wrong, challenger wrenches are very good and I buy every one I find cheap. i am hopeful the blackhawk wrenches that took their place become the new craftsman. Time will tell.