What are your thoughts on neutering male dogs?

I have never owned a male dog before. I might be getting one in a few months, and I’d like to be well prepared.

I realize the impact of neutering differs from dog to dog, but in your experience, what changes could I expect? Have your dogs been easier to manage afterward, as many claim? Have they been calmer, more insecure, or simply less attracted to females?

Please state at what age your dog was neutered.

PS: I am also very interested in any science you can provide!