Eileen and
Aileen are dated and not yet ready for a comeback.
Irene is already starting to come back.
I imagine an
Eileen to be plain and quiet.
Aileen makes me think of a serial murderer because of
Aileen Wuornos.
I had an aunt by marriage named
Irene so the name makes me think of her. She was an averagely attractive woman with a loud voice who moved her dentures around in her mouth a lot. She was nice enough. It's not either an overwhelmingly bad nor an overwhelmingly good association.
Come to think of it, I had a great-aunt named
Eileen but I saw her so infrequently before she passed away in 1984 that I really couldn't say what she was like, so she left me with no association with her name.