I have to tell this as it is. We have been 2x to the US for cruises via Miami. It is the most dreadful experience we have ever had. Firstly we were approximately 300 British cruise passengers arriving late at night in Miami. We were tired but we do know how to stand in lines. It took an average of 2 hrs for us to get through immigration that night and 3 hrs the next day!. There was no refreshment available and nowhere to sit - terrible for elderly people in particular.
The attitude of the immigration staff was absolutely dreadful. They treated us as if we were about to invade the country - they were aggressive and unforgiving if one failed to understand their questions ! Hey - we are the British - your friends and (only?) Allies.
We all thought it was right over the top and very much 'lets play soldiers and abuse everyone' It really was embarrassing to watch them strutting their piece.
A huge number of people said they would never ever go back again. It is a real shame and this OTT approach does not go down well.