I pronounce
Layla,
Laila and
Leila all the same - "LAY-luh"
Pronouncing
Leila any other way than "LAY-la" is weird to me.
Leila is my favorite spelling, followed by
Layla. The thing is, I don't actually know of any (human) Laylas (et al) but it has always seemed really trendy to me. It's a name all the girls from my generation just love and bestow upon their dogs only because they don't have any actual children.
Lila I intuitively pronounce "LY-la" but actually prefer the sound of "LEE-la." It appears less common than
Layla but it's still pretty "mainstream". I might like it more if I didn't have bad pop culture references for the name - There was a
Lila on the TV show
Dexter who was absolutely horrid and right now I'm watching Friday Night Lights which has a
Lila who, while not actually a bad person at all, I'm just not keen on her character. I'd prefer
Lilac :)