[Piotrsko]

Unless they make a split cone shaped wire socket, you get a small point of contact where the sharp edge bites into the wire (and reduces it's diameter, increases resistance)
Still aint going to use backstabbers, and I have a couple of bulk boxes of the traditional screw sets in white and ivory from when I replaced them all in my current house

Look for ring indent on wire. Thats where the wire will fail.

Edit: went to orange store, looked at new style, didn't see UL mark on boxes I saw. Wonder if they are legal, not that that ever stopped orange store from selling stuff.

Other joke, last year was bumper snow storm year, so there's a hundred snow blowers chained up outside, not selling