When I first received the cups, I found them awkward to use for measuring heavy opaque epoxies since it was extremely difficult to read the measurements on the side of the cups when I have stuff in them. To remedy this, I now rotate the cups on a table and mark all around the level I need with a Sharpie.  I find this to be better than other "marked" cups. I had also chosen these cups specifically as I didn't want any internal support nibs and didn't see any in the picture, but they do contain small nibs.  Finally, because they are flexible, by squeezing the cups I can get the epoxy components to quickly level off, something that would not have been possible with a rigid cup.