I am not an EC.
I have personally seen the effects of push-in terminated devices. (Some of my photos are posted on the board.)
If there is a screw that is used to tighten the connection, such as with the GFCI receptacles (the ones that have a back-stab hole but require the screw to tighten the connection), I don't see a problem.
If one is relying on a spring type of connection, then I would not trust it.
I have also found that the screws provided in some of the cheaper devices are almost as soft as the copper, and are not very sturdy.
If I understand correctly, 12AWG can no longer be used with push-in connections, right? Why is 14AWG permitted and not 12?...