So, I was able to use GE lane at JFK on a recent out of country trip. It took less than 2min for 3 passports. I didn't see anyone else in GE lane - I think my flight was only flight deplaning at that time else its hard to see JFK POE with relatively thin crowd. Many folks were in the APC kiosk lane.

Couple of things:
- Since there is no stamping so receipt generated by machine is only proof of entry. Two receipts are generated for non-US passport - one was kept by the officer while existing immigration zone. Other was for us to keep. This receipt is not I-94. I was thinking it to have I-94 info as well but it didn't.
- I-94 will get generated electronically like the way it works.
- All the dates and other visa information were correctly pre-populated after scanning the passport. So, we just had to hit next.

All in all, I do enjoy having NOT having to explain the "purpose of visit" and showing I-797 at POE. That's more valuable to me than saving few min of time and breezing through. That gets negated by baggage claim time anyway unless I start making international trip with just hand baggage.