We normally fly to MIA, and as I haven't flown to MCO for a few years I can't offer a direct comparison.
About MIA, though. It seems there have been some changes to immigration in the last year, as this time when we arrived we went through an immigration point near the arrival gate, not to the main, large immigration room. We still had to queue up, but I guess they're doing this to alleviate pressure on the system. I've never really had any problems with the airport though.
We flew AA last year, indirect from STN-JFK-MIA. Was a bit of a nightmare really. On the way out the JFK-MIA leg was delayed a couple of hours, but the return was worse. We unluckily got caught up in some massive aircraft safety recall thing that affected many US airlines and meant lots of planes/crew were in the wrong place. In the end there was confusion/delays, with the stress of missing the JFK-STN connection, but as it happened that connection was also delayed so we caught it in the end (minus 1 bag).
The result of all this is the DW wrote a letter of complaint and we ended up getting an $800 travel voucher as compensation.
Onboard, however AA was fine, and we're flying to LAX next year (direct) with them.
It has made me appreciate the value of non-stop direct flights more though...