1) ASFs have little to no odor. Because they are a desert species, they don't urinate as much as mice and rats in order to conserve water.
They also have a designated 'potty corner', where they only defecate in that one corner. It makes spot cleaning very easy. They have huge litters, but grow very slow. Can get aggressive or nippy when pups are around.
2) Norway Rats themselves don't smell much. And while they are very clean animals, they do urinate and defecate fairly often, which is what builds up. They need weekly or bi-weekly cleaning. Have moderately sized litters, but grow very fast. Rats have the best temperaments.
3) Mice have a very strong odor. They urinate and defecate very very often. This is the main reason they smell so awful. Male mice mark A LOT. Have moderately sized litters, but grows fast.
I cannot keep mice. They smell terrible. 2 mice can smell worse than my entire rack of rats.
A mouse cage will smell just hours after changing bedding compared to days with rats. It takes about 5 days for my rats to start to smell after a bedding change. Keeping uncrowded cages will help with the odor as well.
ASFs are still by far the best in regard to maintenance and odor.