well, i've got a 6 month old on live right now but i will be switching to f/t for financial & safety reasons.
i wasn't able to let my girl's breeder switch her to f/t because we werent able to get set up for it (purchasing a seperate, mini freezer for the frozen rats as well as the rats themselves.)
as far as finances go, this is the math i came up with...

what i currently spend on rats, bedding & food p/ month - $40
that x's 6 for a 6 month time frame = $240

1 20-25 ct pck of f/t rats = $60 (s&h included)

but that 1 pck will last approximately 6 months so i'll only be spending $60 in 6 months to feed my snake rather then the $240 buying live rats and supplying their bedding and food.

i've always known that feeding p/k or f/t is safer in the long run and it was never my intention to keep my snake on live forever but i would rather take away any potential risks for injury when i feed my girl then have to deal with the potential for a big vet bill when the problem can be avoided in the 1st place.

granted, in the wild these snakes eat live food and they deal with injuries and go on living. it's just a fact of life. something must die for something else to live. it's just the way it works.
i'm not completely heartless though. i do not like putting a defenseless animal to its death every time i feed the snake and i will be resolving that issue soon.
whatever situation works best for you, go with it.
good luck.