Arrived MCO in PE on VS73 in November. Kept on the plane for 25 minutes as "immigration line is full".. then queued for over an hour (those travelling in Economy would have taken a lot longer). Only half the immigration booths were open and the arrival of our flight (during the peak period for transatlantic arrivals) seemed to occur during a shift change or lunch break. My sister flew out the week before to similar chaos and the following week we were joined by our sons who took over two hours to get through. The immigration officer we saw was very polite and explained that 3 international flights had arrived within 10 minutes of one another. I resisted the temptation to comment that this was an airport and the arrival of 3 planes around the same time - particularly as they were scheduled to arrive together - should not be beyond the capabilities of a country who put man on the moon! Orlando is the most visited tourist town in the USA - if they want visitors they need to get a grip and sort this mess out! What will summer be like with Virgin alone having 6 arrivals daily? Does Virgin Atlantic discuss these issues with the airport authorities?
There was a long thread about it recently here.
It really is just down to luck, sometimes if your flight arrives without others you can be through in minutes, but if 3 or 4 747's all arrive at the same time due to delays etc then in all honesty a lot of airports will and do struggle. MCO is set up to receive the a/c but no matter how many officers they have if you suddenly dump 1200-1500 in the immigration hall at the same time it is going to take a while to process them all.