Differences I see in Ripley now vs. when he was intact are behaviours directly related to hormones (or lack thereof).
The only changes I've seen are: He no longer obsesses over sniffing and licking the girls or where they have sat. He no longer feels like he has to urine taste. He no longer is obsessive about marking. He no longer humps out of over excitement, although that one could have been age related rather than just because of being intact. But he used to air hump if he got over excited when playing (with males or females) and that disappeared completely after being neutered.
I expect a lot of my dogs and train them so it's not like he was an out of control marker or humper or anything. He was really pretty easy all in all. The only things that made him even a little difficult had nothing to do with his intact status and everything to do with being a brainless teenage wonder. The only difference between him intact and now is that I no longer have to keep any of those most annoying behaviours (urine tasting, air humping and marking) in check, because two behaviours have drastically declined and one is non-existent.
He is still a boy and he still marks, but it's not a compulsion like it used to seem to be. He still urine tastes every once in a while, but again, it's not a compulsion. And to be honest, both of my girls have done it on occasion as well. I could have lived with Ripley intact for his entire life had I wanted to, but the humping and the urine tasting/obsessive licking of wherever the girls sat (in the house or outside) was annoying and it was nice to be rid of those. The only reason I actually neutered him was because he was starving himself and was impossible to get him to maintain weight for any length of time.