Even when feeding f.t. the snake will still go through the same killing process - they just do it with an already dead rodent. Your snake shouldn't have any problems taking a live rodent - he may be a bit scared of it moving around but he'll get used to it if that is how you intend to feed.

As for the nutrient content about the only thing you loose with f.t. is a bit of water. Whether its easiest for you to feed live or f.t. is a personal choice - sometimes it's just easier to know there is a pack of 20 in the freezer rather than "will there be one the right size" at the pet store.