This floss is definitely best for people with widely spaced teeth, and not very good at all for people with tightly spaced teeth. If you have both as I do, then you might have a love/hate relationship with it. I'm not sorry I bought it, but I'm not sure whether I'll buy it again or not. I might buy some to have on hand for when I get those stubborn food bits stuck up there and my normal floss isn't cutting it.
This floss is made up of many gossamer-thin strands twisted together in such a way that they expand and separate when you give the ends a tug. That "webbing" is what allows it to capture more food particles, even the ones deeply embedded in the tooth pockets.
I can use my normal waxed floss or tape, and follow it up immediately with a second flossing using this stuff, and this always gets a few particles that my normal floss missed.
However, because of the unique construction it shreds very badly when you try to pull it out from between tightly spaced teeth, leaving strands of itself stuck and requiring more floss and a lot of elbow grease to get out the fine strands.
It's extremely thick, so you can't force it between very tightly spaced teeth at all. If you do manage to force it up in there, sometimes the only way to get it out is by drawing it out by one end. If you have tender gums, that can be painful.
It's not smooth at all, but textured. That might be good for scraping off tarter. It definitely makes it harder to get in and out between the teeth.
I hope that this has helped somebody to clarify the pros and cons as I experienced them.