Longest was 2 hours. This was during the masses of people arriving for OTC (Oil show). Quickest from Landing, deplaning, clearing immigration, collecting bag, clearing customs, and being on the car hire shuttle bus was under 45 minutes - I was impressed.
The problem I find is that they actually have people assisting with the queues at immigration who have obviously NOT attended an effecting queuing training course, as I really believe everything would move smoother if they just stopped trying to help.