If you only have 2 hours between fights given how slow bags are put out at MIA (easily 45 minutes+) checking a bag is going to be risky. You will have to deplane, head to baggage claim, get your bag and then recheck it and re-enter Security. If you don't have Pre Check (and even if you do) Security at MIA is a nightmare. I would never check a bag at MIA with 2 hours between flights.