Putting aside the question of whether or not prison is "enjoyable," the answers might surprise you. I've always heard that relatives of murder victims want the killers killed, but in my personal experience that has seldom been the case.
Ironically, and with no disrespect to them, the opinions of those who were gravely injured are irrelevant to the discussion, because absent the death of others, Tsarnaev would not be eligible for the death penalty and the question would be moot--no matter how hellacious the non-fatal injuries were.
Tsarnaev if asked would probably tell you if he had the opportunity he would kill the survivors and if he had the opportunity to take out a non-Islamist would do so. His
hatred for Americans, Christians and Jews is undying, nothing will change his belief because it would be against his religion. I wonder if he had taken you out how your family would vote about his imprisonment if he was convicted, personally, I would want to have him executed just as Timothy McVey was. Resolve the problem so that the victims can bring this episode to a conclusion.
I am happy that I don't live in Massachusetts they have not only paid a high price in death and pain, but the costs for the trial and appeals which will follow are going to be in the millions.