Aer Lingus is a slightly weird case; they have essentially become a budget airline (at least for their European business) to compete with Ryanair, but they haven't yet gotten around to adopting most of the dark patterns.
Well, the thing is they historically weren't a budget airline. They've taken on some budget airline attributes, but mostly not the dark patterns. Yet. They'll get there.
Ryanair is the biggest airline in Europe. Everyone competes with them. I found if you are traveling with family, need a checked bag and seats - Ryanair has no price advantage over other players.
Their trans-Atlantic flights are ok and cheap relative to United (out of IAD, to points in continental Europe). Their EU flights are a noticeable step down.