I would say go for it. I know people that swear by them. I have herd if you want to see the length/width explode feed them rabbits.

I sadly haven't been able to find anyone locally who breeds rabbits to make it worth the switch from rats to rabbits for my smaller stuff, but if I did I would. The only thing I have heard is that obviously the bones in the baby rabbit are not as developed as an adult rat. I wouldn't completely stop feeding rats but substitute a few rabbits biweekly or something.