I feed both.
I prefer F/T and that is my main method of feeding. For many reasons. It is convenient for me, I don't have a reliable "live" source, I don't have to worry about injuries, my collection is small enough to where it is actually less time consuming to feed F/T.
However...I would NEVER ever not feed a snake live just to make a point or because of my own morals. I have hatchlings and they simply would NOT take f/t as their first meal. So they got live mouse hoppers. At this point I have switched ALL of my hatchlings to f/t. Most of them to f/t rats, a couple still prefer mice. It takes time and patience, but in the long run it will give the new owners "options", so its worth it to me.
The only thing I have a problem with is when people either don't take the time (or research) to do either method RIGHT and then complain about it. Or when people are so close minded that they feel its THEIR way or the highway. Or when people starve their animals rather then to give in and feed them live until they can slowly, safely and patiently be converted to F/T.