I've been to IOP at two different hospitals. The first hospital I found it was very helpful, and it was a good step-down from inpatient. I saw a doctor everyday and had groups. The groups were CBT/DBT related and it was very helpful. The second hospital did nothing to help and didn't have good groups at all. It was not helpful, but more of someway to babysit me until I could manage on my own.

I think IOP is good, but make they're actually doing something during groups/etc to help you. If it's just fluff to fill in time, it was no more than a babysitting service. But good IOPs are definitely worth it.