I do WW Online, but in the past have done it just "at-home" with materials I purchased for it. I haven't been to any meetings since the very first one I went to a couple years ago, just to get the start-up materials and an initial weight. It was a free registration time, so I figured I wasn't losing anything.
From what I understand, "Simply Filling" is basically what Core was, and "Momentum" is basically the Flex plan, just with encouragement to use your points on more filling, whole-type foods, more than using them on just anything just because you can. I mean, you still can use your points on whatever you want to, but I remember being on here back then and reading posts from members who knew people who spent most of their points on junk food because they could....but those people weren't exactly staying full and weren't necessarily eating healthfully, even if they stayed within their points allotment.
"How can you say there are too many children? That is like saying there are too many flowers."-Mother Teresa of Calcutta