It's not as bad as some people say. I've been to one twice, and each time I met some very nice people my age and with similar issues (suicidal thoughts, depression, self-harm, etc.).
The staff people are usually friendly but depending on where you go, you just might find an @sshole or two (I experienced a few on my own, but that's another story). They generally just want to help. There's a lot of group therapy, which can be helpful if you try and get a lot out of it, but the textbook tactics of feeling better (coping mechanisms, positive affirmations, blah) got a little redundant for me.
It's almost positive that they will force some medication on you. It's the main goal of these people to get you on some sort of drug so that you'll feel like you're feeling better. Sometimes, they work. In my case, I was prescribed many different meds but ultimately I have quit them all. I'm not saying they can't be helpful though.
Anyway, you don't get to go outside (I assume?), the food is alright (where I went anyway), lots of group therapy and I would expect medication. People have made lasting friends there. For me, being a socially anxious person, I found the social aspect with people my age very difficult, and I think that was the ultimate hindrance toward my getting better (because after a while you just want to get the hell out of there). On the other hand, there were some kids doing anything to stay. So, everyone has different feelings about it.