I don´t mind cribs. If the toddler´s needs are ok, they usually don´t make a fuss, just sing to themselves and pick their cute little noses. The biggest problem with cribs I have are not the toddlers, but the adult sims, because at night, or if they are really tired themselves, they put the child in the crib, even if it isn´t tired. I often use (and absolutly love) the toddler napping mats from modthesims: http://modthesims.info/d/593159
They can access and leave them on their own, and you don´t have to let them pass out on the floor.
I also feel the swing is kinda cheaty, and I normally only use the playpen for children who already can talk, walk and speak. If you put two toddlers in it, it makes them best friends and gives them a head start at charisma.