[QUOTE=Smirnoff;14074973]We're also doing the LHR-MIA-Costa Rica trip next month, but to LIR rather than SJO.
As an extra piece of advice, I would avoid any tight connection anywhere, especially at MIA. We avoided a 2 hour dash to our connnecting flight and opted instead for an overnight stay at the MIA Hilton, and a leisurely onward flight in the morning. I hate seeing stressed passengers on longhaul flights, freaking out about missing their onward connections.
I would echo the comment from Smirnoff. Our connections from LHR to SJO at MIA were fine, but the return flight from SJO to MIA on AA was severely delayed. I think there were about 12 passengers aiming to make the connecting BA flight to LHR. We had only 75 minutes at MIA, including time for baggage retrieval, immigration and to get through to bag drop for the BA flight. We were escorted all the way through from the baggage hall by a very helpful member of BA ground staff to the BA gate and it was the only way we would have made it. The last passengers were boarding just as we arrived. Even with a through ticket, it was still very stressful.