I have found that Dollar has the best rates at MCO using the KISS2 rate especially if you book 6 months in advance. Remember bookingf rentals cars (unlike airlines) they don't charge your CC at time of booking you can cancel at anytime and you can change your ressie at any time without penalty.
My suggestion overall is to join whatever rental car companies "club" this will have MUCHO time when getting your car.... like walk up and drive away versus waiting at the desk. FWIW... most of these clubs are free of charge!!!