The sugars are another story.
The sound: I have experienced squeeking. They might have improved the formula since, and better technique might eliminate the problem. Other than that, when they dont squeek the sound lovely. And definitely more bright than Nylgut as promised.
The feel: Even when they dont squeek, they feel squeeky to the touch. Like a bit plasticky, stiff and brittle. It is not as bad for me as the grainynes of the carbonblacks, but I am not a super fan.
Over all, I prefer to go either Nylgut or Fluorocarbon rather than the sugars, depending on the sound I want. But it is probably a matter of getting used to them, and if it of the outmost importance for you to get something brighter while avoiding fluorocarbon - they just might be right for you.
They do sound nice.