Hello. Based on my 31years in the health care business, an individual plan is clearly the better option. Benefits are richer, the Network is larger and in the event of a catastrophic or ongoing major medical treatment, you will be better protected.
A group co-op depends on a constant stream of subscribers and moderate medical expense usage. If that stops, members are in trouble.
Of course, if you are uninsurable and your state risk pool insurance rate is high, give the co-op a try, if you can qualify.