Should I get iPhone 5, or wait for 5S(or something)?

I was just blown away by MacBook Pro Retina I bought last week, and that led me to sudden craving for iPhone 5. How do you guys using iPhone 5 evaluate it? Is it completed enough to go get one right now while half of the product cycle has been passed? or is there something to be improved or fixed which makes it wiser to wait for the new one?