In my opinin, Houston Bush has the best designed immigration facility in the US. Maybe that's because it's new! Lots of booths, well manned, and things move right along. Even when a bunch of flights from Central/South America arrive. Well organized (though loud-mouthed) directors keep the booth lines short.
DFW is not too bad, but nowhere near as good as IAH.
No opinion on lounges. Out of my pay grade.