Rabbits need more space. If you're going to have multiple rabbits, you need to keep them in a place that is well ventilated. Rats can be kept in a fairly small room... much like a reptile room. Bedding, cages, bowls, food... it all adds up fairly quickly. Ask my roommate... she has one for a pet. Just one. And it costs her quite a bit.


Rabbits also eat quite a bit more than rats would... obviously because of size.

Rabbits just require more care in general than rats.