I guess I must have been lucky on my trip to Florida with US MAN-PHL-MCO a couple of months back! Paid for an on-the-day upgrade to business for the transatlantic sectors each way, but it was all OK, though not spectacular (are any any more?).
Was first at immigration at Philly, so the time between getting off the first flight and joining the 20 minute security queue to go back airside was 15 minutes! I suspect that a degree of luck was involved given the rush of international flights that arrive together - we just happened to be first in on that day.
Probably reflects my expectations and infrequent long haul travel these days.
I even spotted a member of the cabin crew who appeared to be under 50 on one of the domestic legs!