All I can add is, as my husband (McAdry) said we mostly feed rats to our collection (with a few mouse eaters as well)and do so because it's convenient as we breed our own rats here at home.
I have though compared our small collection with Robin's (rabernet) - she feeds exclusively mice, we feed rats. Basically comparing snakes of the same gender and very close in hatching dates we can't see any significant difference in growth at all. Her mouse eaters may be eating two mice where my rat eaters are eating one rat but basically the total volume of prey is the same per week. We have BP's here that are quite large for age on a relatively low amount of prey volume....that I suppose is due in some part to their genetics for growth.
This is of course, completely non-scientific, just our observations recently when we were discussing this whole mouse/rat thing.
Where I've seen a big difference is with boa's. They grow so much bigger and faster that we found a huge jump in size in our almost yearling boa when he was put on rats. Seems his needs were quickly surpassing the number of mice he could snarf down weekly so rats just work better for him and being his mature size will necessitate large prey, rats just make sense for him.