I prefer to feed rats over mice mostly for the convenience and savings of feeding one prey item vs. multiple prey items. I'd rather feed a BP a single medium rat as opposed to 3 jumbo mice. For BPs it's not too bad but for larger snakes it wouldn't be practical to feed 6 jumbo mice vs. 1 large rat. The prey sizes are pretty similar for our younger snakes it's just sometimes harder to transition them to rats as they get okder so I think it's best to make the switch early.