I don't know if Mac OS is different but on other unices ports above 1024 are not privileged, meaning that anybody can bind them. Now it increases the attack surface only a tiny bit (you have to have your sshd offline, and the attacker have local access, and them bind a fake sshd to your port in order to MitM. And even then they won't be able to spoof the server key unless it's not chmoded correctly).
Still, better safe than sorry IMO, I also use a non-standard sshd port but I keep it in the low range. In my experience it's more than sufficient to get rid of 99% of dumb attacks that generally don't bother looking beyond port 22.
My personal suggestion though is to use 1022 because it's below 1024. This means only root is allowed to bind to it. Preventing possible connection jacking attacks if an attacker is able to crash your own server and run theirs to harvest your passwords.
> So, I tried ssh ip-address -pXXXXXXXXX