Hi Caroline,
There's a few of us here doing it online (including some fantastic successes - cocktail princess, fillymum and several others I'm sure). I absolutely love it. Have done really well. However it is more difficult in some ways, because there's no-one (but you !) to answer to. I love the prompt to weigh in every week (although I know exactly when it's due, it just helps to put my weight in every week and track the changes) and am very reluctant to discontinue the subscription even though I have all the books and know the plan quite well.
I think it depends on you though and your motivation. There are people here who would never be able to manage without the consultant and group atmosphere, and others who would never go to group (for various reasons). Neither should feel bad/guilty but you need to be realistic about what you need.
Good luck.
Gail x