IAH is pretty good with regard to the TSA side of this speed thing for transit passengers, but the CBP side has often been a slow beast when I come in that way from abroad. DTW too had been pretty good with regard to the TSA times; but due to the CBP side of things at DTW, DTW has fallen further behind IAH for my preference. [In the case of DTW, part of the issue has been that the stream of transit passengers just seems to hit the TSA screening checkpoint in bigger waves after CBP

IAD is one of those places where I have often done better by avoiding the mid-field terminal processing when doing onward connections from there. For me, it's worse from the TSA side of things and also from the CBP side of things.

IIRC, it's been at least several years since I came into SEA on flights from Asia/UK/Schengen countries or on other non-Preclearance flights, but I recall those transits at SEA being sort of an easy deal with TSA post-CBP the last times I did it.

But this all is sort of like a "pick your poison" thing since each of the major US airports of entry for transit passengers have there mix of pros and cons depending on the circumstances.