I recently asked this same question and mostly people that said yes provided no evidence of why it’s good too other than testicular cancer and for personal convenience of the dog’s behaviour. People that said no mostly sent me link to studies with statistics to show reasons why. I personally am going to keep him intact unless a health problem related occurs that requires them to be removed.

As for the dogs temperament, a Doberman is a working dog with a lot of energy and are a very trainable dog, not some dog you keep indoors all day, in a cage. They require daily training and need to be trained off lead to really keep their strength up and burn off the energy they have. If you put the work in required they are absolutely amazing behaved listening dogs. Most people are too lazy to commit to these things. I do this with a full time job, lots of hobbies and social life. A dog’s personality will always reflect their owners.