I wouldn't be as concerned about neutering early with a male as with a female. With females I'm strongly in the camp to have it done before their first heat due to the risk of cancers. With the males, it's more about behavior problems like marking, running away, aggression, and the drive to get to a female if they smell them while they're in heat. But I would say anytime after 6 months is ideal. If you don't see many of the associated behaviour problems I don't see the harm in waiting until around a year if you want him to be finished growing. And as for coat, I do hear it changes slightly but honestly I wouldn't be able to tell the difference and it is definitely not a good enough reason to not neuter.
Lady (1.5 year old tricolour) & Gracie (4 year old blenheim)
"Happiness is a warm puppy" - Charles M. Schulz