Municipal hospitals are probably like the hospitals you're familiar with, with maybe plus or minus the perks. There may not be as much occupational therapy, or resources on the ward. But it's not too bad. Private hospitals are a lot nicer but generally wouldn't want/allow a pauper patient on their psych ward if they have one. I've never been to a hospital that's only for psychiatric patients. The two hospitals I've been to for this were pretty nice, really. And both were public hospitals and accepted my insurance and I got free rides because of being eligible for the medicaid assistance.

A lot depends on which state you live in because medicaid eligibility varies from state to state.