I bought the heavy duty strippers after my previous strippers succumbed to failure at the rivet joint (too many instances of abuse, such as turning wire nuts with them.) Overall, I don't like them functionally, but they're a durable plier that feels like it will last FOREVER (much to my chagrin.)
I've had the new pair for two months, they have good fit and form in my hand. They feel more like a Linesman plier. The grips are thick, but nut bulky like goofy Journeyman pliers. The locking tab on the hinge is very slick and intuitive, and ought to be replicated on the cheesy metal stamped stripping pliers (that I will eventually return to using.)
However, when stripping wires I feel like I have to use excessive force to expel the stripped insulation from the wire versus my previous pliers, almost like the tolerances are so close to create friction on the wire.
But what bugs me of most of all, and makes me wish I hadn't bought them, is that you can't make loops for devices with these pliers worth a crap, because there is no little keyhole in the side for such a purpose. I've had to manually form loops for 2 months now, and I hate it.