If you have time, find out as much as you can about the hospitals in your area as possible through their literature, word of mouth, and internet. Be aware of the motivations of those you speak with. Remember that those working for a hospital will be less likely to share negative news about it. And someone who has had a bad experience in a particular hospital is likely to forget to mention anything that might have been positive about it
Most important are the reputation of the experts who practice there and their research. Hospitals that specialize in psychiatric care are more likely to attract the experts. In my limited experience, I got better care at a hospital that specialized in psychiatry than I did in the psychiatric ward of a general hospital. The psychatric hospital was stricter in its rules, which I found more aggravating at first. But in the long run, they were the biggest help.
The flexibility of their rules and what you need or will feel comfortable with.
Advice from outside therapists, family members, and friends can be useful here,
but remember they can be as biased about you as you can be about yourself.
If you need boundaries, go for more and stricter rules. If you have authority issues this may be an opportunity to work them through. However, as they no longer do therapy at mental hospitals so you will need to do this on your own.
If you tend to be hard on yourself or overly disciplined, you may need a softer, gentler, more flexible environment. If you have authority issues and think that a strict ward would just cause you to act out, go for gentle.
In trying to learn about the rules remember that the hospital may not want you to know how easygoing they may actually be. They are afraid of attracting patients who will just abuse the system.