Talking to former inmates (an unfortunate consequence of working LE), I think the media stereotypes about prison are a little off base.
Most cons say that (in Texas at least), rapes are pretty rare, andprison violence is pretty infrequent, and usually limited to those who are in prison gangs. Their worst gripes are:
-No AC in most Texas prisons;
-No tobacco;
-Food is ghastly;
-Crappy medical care (this is big scandal now, with inmates dying from easily treatable stuff or getting treated by quacks).
Most folks who get arrested are out on bond the next day, and if you haven't been in trouble with law before and didn't commit a very serious offense (arson, burglary, rape, robbery, agg assault, murder), you can probably get out of every goin to jail to jail again; probation and deferred adjudication or deferred prosecution seem to be really popular, these days.
From my viewpoint at least, I am confident that every person I have sent to prison has committed every offense that that they were charged with. I either personally observed the offense, they confessed, or I collected good, clear and convincing evidence. If I wasn't sure that someone did an offense, I would make sure that the prosecutor knew how I felt, and I would testify accordingly. I sleep soundly at night (unless my wife is kicking me).