I'm on ProPoints. I find the weightloss is slow, around 1lb a week (after the first few weeks with the bigger losses), which I sometimes find frustrating, but the losses are always consistent and when I have been pointing correctly (which I always have, aside from 2 weeks when I was on holiday), I have not gained weight.
I do sometimes get frustrated with the low losses and how long it is taking but I've lost weight steadily since I started, I'm never hungry and I can still go out and eat and drink with my extra weekly points.
With PP foods are pointed a lot higher, if something has 2 points on discovery, it will likely have 4 on pro points.