I've had intact males, neutered males, intact females, and spayed females, heh. In general, as youngsters all are fairly active and want to explore. They seem to enjoy handling, but want to run around and check everything out too!
As they got older, all calmed down, but the boys calm significantly more. Most of my boys, intact or neutered, prefer me coming to them, rather than coming out of their hammock to me, LOL. They just like they idea of lounging until I give them a good reason to come out, or I go there to get them out myself. My girls generally stayed more inquisitive, and were more likely to come out and check stuff out vs. waiting for me to bring stuff to them as they got older. So it depends on if you want one that is going to remain more active and inquisitive, or one that is going to become more of a hammock-potato. That said, individual personalities vary tremendously, so some males stay super active their whole lives, and some females are total bums! The stuff above is more of a generalization.
I've not noticed a significant difference in odor levels between any of my different rats - I think alot of it depends on bedding used, caging used (how much ventilation it gets), diet, cleaning, etc. And it may again also be individual or even line differences - some genetics may predispose some rats to having more odor than others.
I think the best suggestion, which was mentioned already, is to go meet the rats that they have available to be rescued, and find one whose personality appeals most to you. And if you find yourself drawn to the females as cuter, go with that - as long as the personality fits. Any gender of rats will make a great pet!