Well I think (hope) that they will have to stay reasonably low with their prices although in saying that they are still more expensive than Ryanair. There is too much competition out there to justify high prices.
Although I always go for the lowest cost possible when flying I do like flying with Aer Lingus, it's a lot more dignified having a seat assigned and as a result not having to be at the gate to start queueing an hour before the flight departs or running across the tarmac.