This is what I posted on another thread recently about my MIA arrival experience:

Arrived into Miami today and had to go through the new arrivals area. Let's just say it was a frustrating experience and even had me missing the old arrivals area! It was a mess before but at least you knew there were certain places where you could get seen quicker.

In theory, the new arrivals process should work better and I'm hoping that there are just teething problems at the moment. I was the first one of the plane and after a quick 15 min walk to arrivals, I joined the back of a huge queue. They are using a fairer system now where everyone queues together and only get sent to individual agent queues when they get to the front. This is theory should work but it failed miserably because there were no staff managing the queue, and instructing people as to which agent queue they should use. The upshot of this was that some agent queues had double line queues and people weren't being instructed, or had the common sense, to use all the available agent lines, leading to a bottleneck at the front. Also the lack of a properly functioning AC system didn't help, nor did the strong smell of sweat that was in the air.

It took me about an hour and 15 mins to clear immigration and then I walked to the baggage reclaim area and I swear i thought I was in India, there were people everywhere waiting for baggage and it was extrememly difficult to pass by people.

Hopefully these are just teething problems but, if not, it seems that it is somehow possible to make the MIA arrivals process even worse than the crap that existed before