You can buy a 1911 for around $500 or you can buy one for $5000+. They are both basically the same thing. You can buy a car for under $15,000 or you can buy one for over $1 million. AR-15 is no different. An expensive one is likely to be better quality than a cheap one. Being worth it or not is up to you. You would likely enjoy owning the expensive one more, but don't count on it to work much better.