I love both. I honestly can't decide between the two. They're both very pretty and sophistocated, and I love mythology names in general.
Leda is wonderfully delicate, elegant, and balances; it would sound spectacular with a long, classic MN.
I like the simplicity of
Leto. It's simple, and I love the fact that there's absolutely nothing frilly about it. It's also very cute, but not sickenly sweet so it would age very well.