This question has come up in family of late,
Victims of crime naturally have a different perspective and if someone killed a member of my family, I would want them dead. In jolly old England, the death penalty was scrapped over 40 years ago and it is extremely unlikely to come back, as we seem to concentrate more on the rights of criminals than rights of victims. Not only are the sentences that are handed out pathetic, jail is somewhere for people to go and play pool and table tennis, go to the gym and chill out and smoke drugs with your mates whilst the guards look on helplessly.
From what I see that happens in certain American States, I would submit that it is less cruel to use the death penalty than it is to keep someone on death row for years with endless last minute stays.
Not all jails are the five-star hotels that you imply here and I would certainly not want to spend time in one on either side of the bars.
Their is a B & B near Spalding which is probably worse than the average prison.