Used FCO twice during October: both times queues for security departing Terminal B (International) were horrendous on a par with Heathrow: allow at least 30 minutes for this and remain patient when others queue-jump. If you wait until your flight shows as 'boarding' on the screens you might not make it through security on time. Check-in desks seem to open promptly 2 hours before the scheduled time of departure and not a minute before: check-in staff do not appear to be competent so allow for a long wait here. However check-in desk locations are shown in advance of them opening so if you arrive early stake your place in the line. Otherwise a crowded rather average airport: delays on arrival of baggage when arriving and few signs advising you of which terminal you need to be at to find your flight when in transit.