Purple
As a means of comparison, I'm also just back from Las Vegas last month, but routed there differently. My experiences were -
DUB - ORD Precleared immigration in DUB, which is a godsend. Flight on AA 767-300, almost full, with no seatback IFE, just overhead screens. Crappy interior, with mediocre service. Arrived 30 mins early as a domestic flight into T3.
ORD - LAS My colleague flew on after 2 hour stopover. No problems. Because my overall itinerary was different, I had a separate booking, and I mis-booked my ORD - LAS flight, meaning I had a 9 hour stopover!! Paid to use the AA Admiral's Lounge to pass the time more comfortably - best $50 of the trip. My flight, on an MD-83 was full, but with a window seat I did manage a doze, before arriving into LAS at midnight local time.
Return LAS - ORD 08:25 departure on an MD-82 - almost full again, straightforward with no problems. Arrived 15 mins early. Very mediocre service onboard.
ORD - DUB 767-300 heap of tin and aluminium which looked like it had been trashed inside. One single row of CRT screens down the cabin, above the centre seats, atrocious overhead bins which didn't always stay closed - most noticeably on take off and landing, and were obviously state of the art when the Wright brothers had the idea of leaving home, and mostly uncomfortable seats. As we boarded (we were the first onboard) an engineer was still working on the arm of the aisle seat two rows in front of ours. As the flight progressed the occupants of that seat pair discovered they had no reading lights, and no volume control for their earphones, or indeed any attendant call buttons. They weren't impressed.
Overall - as a means of getting from Ireland to LAS it worked, but I'm not sure I'd choose to fly AA ever again. They had no style, finesse or even the slightest impression they were trying to compete with other carriers on a prime route across the pond. The aircraft were like well used Transit vans nearing an MOT. Clearing US Immigration in DUB is something I've done several times, and can't be beaten - especially now that they're located in the very spacious and pleasant lower floor in DUB's new T2,