I would say they are definately worth making, i love them!
The way i do it is without sweetner, as i think they taste just as nice without.
I empty a packet into a ramakin (a small pot would do) and add just enough water to make a very, very claggy paste. When i do this, it looks like a big blob of mess, no smoothness or liquid consistancy.
You will look at it and go, "never, thats got to be too thick!" (keep the faith!).
Bung in microwave. mine is 800W and i do my muffin for approx 1 min 20 seconds, take out-carefully cos hot hot hot- and leave it a few seconds, run your spoon around the pot to get it out and there you go!
Seriously, it will be flippin' hot.
Best of luck and take a look at what other people suggest but this is how i do mine and they come out delish! x