I think both of those books are great and must reads.

Hilger’s book is very comprehensive, has hundreds of hand examples to test yourself against and covers certain concepts that Miller's book already assumes you know. Miller's book emphasizes an advanced aggressive game for crushing loose games although I think most of the advice is excellent regardless of the game conditions you play, you just have to apply it correctly which he does explain in the book.

I think you should read Hilger's 1st and Miller's second. But definitely read them both. I've read both of them several times and continue to study them.