After seven years living in Paris, I have exclusively travelled EI when returning to Ireland over the last four years. Yes, on average FR is cheaper but they have different pricing structures - I find EI often cheaper months before the flight, FR usually cheaper closer to the travel date. Aside from that, with EI I have greater peace of mind, better cabin service, better cabin crew, allocated seating, cleaner and more comfortable aircraft (IMO), and closer airport that is cheaper and more convenient to travel to and has more facilities. There is a reason why many Irish ex-pats in Paris refer to Fr as "Low-Lifer Airlines".