Rikers is New York City's Jail. You don't want to go to Rikers.
I have always heard Federal time was rougher. Perhaps the facilities are nicer, but as far as I know there is no time off for good behavior in the Penitentiary, and things are VERY regimented. But I dont know for sure.
I am sure like everything else, Prison depends on the state. Some of NY State's Prisons are old, supposedly very cold in winter but otherwise we are a liberal state and I am sure NY Prison is better than most of the South. In New York we even allow "conjugal visits".
And as for the rate of incarceration, that is Clinton's legacy.