Hi Anne,
I have mostly done this through body optimise online. More recently I have started going to class as well (partly because everyone here on this site feels that it is so useful) because I thought that when things get tough (which they inevitably will do) I would benefit from the support of a group but I haven't really needed it yet. I would definitely not wish to give up body optimise now (I would rather give up group than body optimise) because I feel that the focus of having to put my weight in every week really helps and I am completely honest about it. I'm not sure that I would have been so successful without it. I use the site for other stuff (looking up syns and recipes etc) fairly regularly but not necessarily every week and once you know the plan (or have the books and ideally a directory of syns) you wouldn't necessarily need it. However I know that some people feel that they really need the support/motivation of a group.
I consider myself to have done pretty well so far but there is one lady here (cocktail princess) who has lost 7 stone (I think) to get to target through body optimise and has kept it off. What an inspiration !!!
Anyway, whatever you decide good luck (and let us know)
Gail x