Ok, so I'm not a dieter, a g/f gave these to me as she was leaving the country.

Always a good opportunity to try something new.
Was sceptical at first at just how good a "diet shake" could possibly taste. I liked the Vanilla and Berry flavours. Wasn't sold on the ChocMint or the coffee ones though.
I made smoothies from them and added a few frozen berries and a banana etc. Were considerably nicer than I was expecting from a "diet" type product and would definitely drink them again.
Didn't feel as though it would be an adequete meal replacement though... maybe a replacement for afternoon tea or snack.
As I said, I was given these so had no idea of the price until I wandered past them at the supermarket the other day... EEK! $4.50 per sachet when purchased seperately. If you were actually replacing a meal with a shake, it maybe OK value, but I still don't think I'd be happy shelling out that for a shake.