Which one to buy?

I'd go Shyvana. She's fun and more or less easy to learn. Lee Sin (can) be tricky. I think you'll have a better time with Shy. Either way, I've got a feeling you'll end up getting the second sooner or later ;)

I'd say Lee Sin. He's definitely harder to learn, and he does fall off really late game BUT getting really good with Lee will help you significantly with most skill shots and engaging. I think playing Lee Sin is a better learning experience, and personally he's more fun.

b

b1

You're debating between a monster and a blind person?

Why not both!