For me, the prices have always been the same (to within a few cents for currency conversion). The exception was that airtickets used to occasionally send me a 5 euro discount voucher which I could use against any flight. The main advantage of an OTA for me is the flexibility - I just booked LIS-ATH-PAS with a 22 hour stopover in Athens which was just not possible directly with A3 (even using the more-options/multi-flight tool). This saved me around 30 euro on making two separate bookings (no ATH departure tax due for the connecting booking). So cheaper - yes, sort of. I used Expedia for this booking but I'd rather steer away from the mega-monopolies so I am looking for a smaller, good quality, reliable OTA if anyone has any ideas.