For me class is VERY important.
I have reached target before and thought I could do it alone... wrong answer.. the weight all came back. I thought I could do it alone and I now know I can't.
I need to go to keep in check, and will do so forever!
With regards to finding groups inspirational, I think it hugely depends on your expectations.
The first group I ever went to was absolutely fantastic. The consultant made everything fun and was such an inspiration to us all. That's when I first reached target. I moved soon after, and could not find a group that I found as inspirational after that so stopped going. The weight piled on and I made a few half hearted attempts after that.
This time I made the decision to do it in class, no matter what. Our C is lovely, and just perhaps just a shade below my first C, but I had decided to do it for ME.... and to make every personal effort I could, and it's worked!
I think you need to decide exactly what you want from a group, and work from there. I don't think any group is perfect, and none has the magic wand to wish away the pounds but I think most give inspiration to the majority. You also need to be in the right mind frame. IMO if a group can't work for you, doing it alone certainly won't as it's so much harder.
Good luck in whatever you decide.