"His time at Rullåker had been unstressful and pleasant enough. The prison had been designed, as Sarowsky expressed it, for hooligans and drunk drivers, not for hardened criminals. The daily routines reminded him of living in a youth hostel." (275)
While in prison, Blomkvist found his stay more as an unexpected vacation. However, this is due to the nature of the liberal and very relaxed setting for Swedish jails, as compared to American prisons. Although not all prisons are as luxurious as they are made out to seem, they still beat out the American jail system.

Here are a few images of what a Swedish prison is kinda like. Notice, its probably better looking to start than most college dorm rooms.

Here, we have a couple images of your average, run of the mill American prison. Notice the subtle difference in quality of life.

In general, Sweden has a much lower prison population than the U.S., as it has about 4,500 incarcerated to our 2,266,832 prison population. This is mostly due to the difference in attitudes toward convicts, the availability of rehabilitation, and treatment of the mentally disturbed.
Articles with some food for thought:
http://www.theguardian.com/society/2013/dec/01/why-sweden-closing-prisons
http://www.theguardian.com/society/2013/dec/01/why-sweden-closing-prisons