I go for the ff natural yoghurt and flavour it with strawberry and/or vanilla with a bit of sweetener. I've yet to try the sugar free jelly crystals in it.
Another use for the ff natural yoghurts etc is that you can use them as sauces for your meat, e.g. with a bit of mustard for your steak, or garlic, cucumber & mint for a tzatziki on a pv day, or garlic, paprika etc for a stroganoff.
Cheryl x