All of my Jewish friends (I'm Jewish myself) pronounce
Leah "LAY-uh" based on the Hebrew when it's spelled out.
Most others I know pronounce it "LEE-ah." Some still say it "LAY-uh", butpersonally, I've found it's less frequent among non-Jews.
As pertaining to my preference, most definitely
Leah.
Leia not only has too many
Star Wars connotations for my taste (not that that will matter for everyone) and also, it doesn't look as aesthetically pleasing to me. Too much vowel imbalance. I prefer
Lia for "LEE-ah", as a NN for
Liana or something of the like.