I loved
Oisín until I found out that it was masculine :P It sounds much better on a girl, but I wouldn't use it on a girl. The meaning is nice. I still like it on a guy but find the sound to be quite feminine (close to
Eileen and
Colleen).
Clíona and
Clíodhna just make me think of "clitoris". I also hate
Fiona, the sound is just not my style.