Karma had been eating f/t rats for 7 months with me and then all of a sudden started refusing and this went on for a month. I have her on live mice now, haven't had a refusal. This doesn't hurt me in terms of how much the food costs because my local pet store sells live and f/t mice and rats, and live and f/t are the same prices. Now, both of my snakes are on live mice.
If you have no problem feeding her mice, I would keep her on them. I've heard that neither is more nutritious than the other.