I typed a long post for you but when I tried to load it, it wouldn't go. Darn it.
I had Copper neutered on Monday. It was hard to take him, but I had done lots of research and felt it was the best decision. I created a thread of encouragement to others on Tuesday. The response I received was both positive and funny in spots. Maybe you could look it up.
It has been 3 days and Copper is as energetic as he ever was. I took his soft foam stairs away from the couch to prevent him from jumping too much. He managed to scramble up the couch without them and then jumped right off. LOL I put them back because he will use them when they are there!
I had heard that neutering can curb aggression down the line, but not change the personality. My daughter Holly had her little dog neutered when he was a puppy. A year later and he is still the sweet fun personality that he was.
Good luck with your decision.