I have only had two boys v. five girls, but I have found the girls more independent. Neither of my boys had any issues with marking. One was a racing school dropout and was neutered before he turned 2, the other was a good racer and was neutered at about 4 (I am his second home, so I am not sure exactly how old). Both boys have been goofy love bugs.
But, they are greyhounds, you can’t go wrong