I've never fed live, luckily I haven't had to. I just don't think I could do it. I would have to find my snake a new home if he ever started to refuse f/t for a long period of time. I would try braining, scenting, rubbing the mouse in ivory dish soap, anything, but live. It just breaks my heart.
I am a lot more okay with feeding mice/rats that are f/t. It really seems no different than buying a frozen steak for myself. The feeder was created and born in order to be fed. I also buy from f/t suppliers that kill the mice/rats by gassing CO2 slowly. So they just fall asleep to never wake up.
Being suffocated to death, having their eyes bulge out and their little bellies get full with dribbles of urine from their bottoms is truly saddening. I cannot for the life of me understand how people enjoy to watch an innocent animal be tortured and killed like that. Yes, it is the circle of life, but we are also defying the natural way of the ecosystem by producing captive bred/hatched snakes, so you can't exactly say it is the same as if the snake was in the wild eating a rodent.
Frozen/thawed for the win. If your snake is about to starve to death and you have tried everything under the sun, supervised live feeding might be the only way to go.