I'm of the opinion the toroidal coil is the chief operational component that can only sense what a toroidal can sense regardless of electronica. That said , i'm less than amused that any manufacturer can exclude ,or for that matter include something ,and still pass UL1699 muster
~RJ~
Anecdotal on AFCI...
I know some people have issues with them...I have not experienced random tripping with the newer gen products (albeit my res'd sample size is small size since my work is on the utility scale side).
I had ALL the afci receps trip in my house several times over the period of two or three weeks. Sometimes simultaneously, sometimes individually regardless of load. Couldn't find the issue or happen to capture it when I had my Fluke PQ meter deployed (not very frequently) -> turns out the 1/0 OH line into my house was actively arcing during wind and rain. One phase was nicked and arcing to the bare steel suporting neutral conductor. Out of the 8 or so strands, 3 were left....and one of the phases was effectively down to a number 10 wire.
PoCo pulled a new OH line...no more issues.
Spoke with my buddy who was the primary AFCI inventor/engineer at a major breaker company - he said they should not have tripped since some were lightly loaded (under 4A or not at all). AFCIs are not supposed to trip in the absence of a load.
I came away thinking that the mfrs really don't have a good handle on how/when they trip.