I flew into TQO with AA on the first day of international ops last month. Customs on arrival was super quick, less than 5 minutes. Can't comment on the car rentals as we booked a transfer service but I did notice a few kiosks. The ADO bus also runs to/from the bus station in downtown Tulum and is waaaay cheaper than the onsite taxi services.

On departure we arrived 2.5 hours prior to departure (also on AA) and security took less than 5 minutes. Super efficient but perhaps we were also there earlier than we needed to be. Helps that there are only 6-7 USA flights per day and they're not all bunched together. Overall it was a super convenient experience flying through TQO.