My GE experience at SFO on 4/30 at around noon off of an early-arriving UA 900 from LHR, mirrored the other experiences. Although the line for non-US admitees was L-O-N-G and their area was crowded, there was only a small line for US citizens and no line to approach the kiosks for GE. As soon as I printed my kiosk receipt, there was a walking-around officer who took one look at it, collected it, and said that I could bypass going to a booth, and proceed directly to baggage claim. A few others got that same offer -- so quite expedited service for those with GE.

Actually, this SFO situation mirrored my arrival a week earlier into LHR: got to immigration at 7:30 am to discover a hugely crowded hall for non U.K./E.U. arrivals. Fortunately was in Business, so had the magic access to get into expedited Immigration. Took about 5-6 mins. instead of hours.