Bought the 2x Plus which is what I normally wear and it fits well. I also have to say i recently lost about 30lbs.. I'm closer to a size 18 than a size 20 now. If you're at the end of the 2X size range (size 20ish), then yes, this would be tight on you... go for the larger size.

As far as the material... it's slinky and soft. I was looking for a light weight, short summer robe and found it in this purchase. The boyfriend likes it too.

I'd buy this again.