My son had two rats, Sugar and Ray.

They didn't smell much at all, actually. It's mostly in how clean you keep the cage, of course.

I've never had a pet mouse, but I've had hamsters, gerbils and rats. Of the three, I can tell you by far rats made the best pets. Not necesarily the cutest or fluffiest, but by far the smartest, cleanest and sweetest.

Our rats used one corner of their big cage as a "toilet" and never made much a mess anywhere else. My son taught them little tricks for food, and they rode around on his shoulder.