I've got a couple. They're decent. I've had Sandvik 12C27 hold and edge better and resharpen just the exact same.
I've looked at mine many times, and never been able to see a temper line, so I couldnt' tell ya' 'bout that.
I've never broken one, but that's not saying much...it's been years since I've broken anything.
I've heard alot of good about them, but so far I haven't seen much to inspire me to carry it any more than my stainless models.