In a past life my business partner and I did live feeding, mainly because I wasn't well educated at the time, he didn't like having to thaw frozens and it meant at least one of us got to go into our favorite local reptile shop to buy feeders at least once a week. He was not diligent though and decided to leave live rats in tubs with snakes overnight on two separate occasions, the first was not immediately fatal to the snake, but I doubt she ever fully recovered, and the other was fatal by morning. I blame this entirely on the business partner, not the snake or the rat, but it can happen.
I my newest endeavor however, I'll be going it strictly with frozen thawed. Not because of the "danger" of live feeding, but for the cost savings and the convenience. Sure, it takes a bit longer to thaw them out and prep them for a meal, but I have the time. I have an old lady, 4 furries and soon to be several rabbits I have to make the rounds with every day, so adding one rat thaw meal every few days is no big deal at all.