WeightyKaty - I've also done WW in the past, and agree that the 'old' WW is just another method of calorie counting. 70 calories = 1 points, and 4g sat fat = 1 point I used to get 18 points a day, so a max of 70x18=1260 calories per day, if you eat zero sat fat. By the time you add in a sensible amount of sat fat, then calorie intake is probably quite low (and certainly lower than on MFP).
The 'new' WW is no longer about calories, but instead about fibre, protein, fat and (something else - can't remember!). The method of calculating points in much more difficult (ie you can't just remember the 70 calories and 4 sat fat and do the maths in your head), so you do need access to their calculators. I'm no nutritional expert, but I suspect that by counting a combination of fibre, protein, fat and ?, you end up on a low calorie diet anyway.
In my opinion, MFP is superior as it's easier to count calories (no working out points etc), and it's free.