It depends on your situation. In my situation, i would MUCH rather be feeding rats because of my supplier. My rat supplier sells me small rats for $1.00. Where as my mouse supply is, unfortunatly, Petland at $1.29/mouse. I have one bp that refuses rats and takes 2 mice per feeding, which equals 2.58 (not inculding tax...my rat supplier sells them tax free )

But that's not really the question...I heard a long time ago that rats were better for bp's..I even noticed a huge change in size after i switched to rats. My preference is rats, but i have no facts to back up why my snake gained so much more weight after switching to rats...