I don't like how the nylon plates "dimple" when the screws are tightened. I guess you have to leave them loose to make it look right. Just has a cheap plastic look compared to the hard plastic ones...(boy that sounds dumb...)
I use metal plates with handy boxes or in commercial applications where metal plates are used elsewhere. (Stainless for food services, etc.)And, yes, only with metal boxes.
I do have concerns about the covers having enough ampacity to trip the OCPD during a short to ground. Joe's pics in the violations section give me such a concern.
In using deep handy's with GFCI's, are there metal "Decora" covers available for handy boxes? I haven't been able to find them, and the plastic covers don't fit well on a handy box.
5 Star Inspections