The cons are that the journey takes longer - you sometimes have to wait a couple of hours for your onward flight to Orlando. International flights are Nonsmoking. The cabin staff will remind you that smoke alarms are fitted in the toilets. Carry -on luggage is now restricted by most International airlines. Try to keep hand luggage to a minimum.
Scheduled airlines have a more generous luggage allowance than charter flights.
I read that the airlines release the cheapest seats first. Florida is hugely popular and the airlines do seem able to fill seats without too much difficulty. If you are supremely flexible you may be lucky and catch a bargain but most people like to plan ahead. If you are fixed to certain dates or if you just like things to be cut and dried I would suggest that you book a flight as soon as you can. Direct flights for popular seasons like Easter, Christmas and summer sell out very quickly - if you are set on these times, don't delay sorting out your flight.