Hurrah, a vet that doesn't automatically pressure you in to neutering! I know that neutering can really affect my particular breed of dog ( Irish Setter) and many setter owners keep their dogs entire. My pup is 7 months and marking outside, trying to hump etc but controllable at present. However I have not made my mind up either way as yet and will see how it goes. If he turns in to a real pain and I can't control the recall, I will obviously do my best to train accordingly but not at the price of making our (and Reuben's) lives a misery in the process.
I have been told not to consider it for a while yet anyway as his growth plates haven't closed yet and he is no way near mature - 3 yrs for setters I think

It would be a shame to lose his lovely glossy coat and rich chestnut colour but first and foremost he is my pet and I guess we can live with the changes.