My experience on 10/21 as a transit passenger in AUH on the way to JFK was really easy and quick. Arrived into AUH at 7:15am from IKA. Cleared the first security line in no time, as there was a separate business/first class line.

Went to the lounge, which was crowded, had breakfast, a shave and a haircut, left the lounge at 9am for the 10:20 am flight. My boarding pass said boarding was at 8:50, and the monitors throughout the airport displayed "Proceed to US Preclearance" from the moment I arrived into AUH, so everyone else was already through. By the time we arrived to the security checkpoint before preclearance, the place was empty, no waiting at all. I was selected for secondary screening "SSSS", and the only thing they did was pat me down--didn't look in my bags, etc. Through in less than 5 minutes. I have global entry, but as others have noted, global entry shares the same line as wheelchair pax, so there were a couple of passengers in front of me, none at all in the regular line, so was called to a different agent. He asked me the standard questions (purpose of visit, other countries visited, etc.) and was truly perplexed when I told him Iran for 2 weeks for tourism. He thought I had to have permission from the US government to travel to Iran, and had to look it up on his computer to find "Currently there are no travel restrictions to Iran", and waived me through. Less than 5 minutes, so a total of 10 minutes or less from security to the lounge near the gates. The lounge attendant came through announcing boarding for the flight a little before 10. Most of the other pax were already on the plane, and there was a business/first line at the gate, so walked directly to the front of the line and then onto the plane, less than 5 minutes from lounge to sitting on plane. Arriving into JFK as a domestic passenger was great, though my connection was in a different terminal so had to go through security again, and this time the SSSS got me a private pat down, and everything in my suitcase swabbed.

The whole process worked exactly as advertised. If you're connecting to an American flight at JFK the MCT is still 2 hours, even with preclearance, so not sure how much time it really saves for onward travel.