I filed mine to make a bigger slot and thought I had it set right. Yeah, I was going at it pretty hard having an off weekend and before I realized it the part was done. If the top piece is sacrificial it sure could have fooled me. Mine seems to be not brittle at all really. Now that I've said it I'll probably munch that too.
I was playing around with .45 ACP and I didn't have this issue using large primers. Just seems to be the small stuff. Even then I had it set up great in .38 Special.
Yeah if you're going to have 2 general purpose presses (say large/small primers) then the same press is the way to go if possible. Parts interchange is a good thing. Obviously dedicated caliber is another story. I've heard enough thing about the Pro 1K I've been tempted to get one for say 9mm and/or .38/.357.