I didn't have difficulty breeding gerbils in family groups so long as they're raised together. Even after a month in the same bedding I'd be hard pressed to notice a scent different from the day after cleaning - probably has to do with their extremely low water intake/outtake. Gerbils are cute and cuddly even as adults - feeding them off was taxing my soul.

ASFs breed well in groups and are easier to introduce. After a week in the same bedding you will definitely notice a smell. Regularly cleaning their "toilet corner" helps but doesn't negate the scent - they drink a lot, they pee a lot. Can be cute but occasionally give you the devil's nip - my soul is sound even after feeding them off.

Both are slowish growers. ASFs have humongous litters, gerbils - not so much.