I have a set and absolutely love them. Because I have four different problems with my hands, I've tried several types of needles. I like to switch between materials and shapes to ease my hands and the Cubics have fitted well into this program. I also like the Cubics double points for the same reasons. The only material I can't use is plastic but for anything not needing double points I use circulars. The shape of the Cubics is very comfortable and I can get the needed gauge.
I have two sets: one size four and one size nine. I like the smaller ones better for some mysterious reason. They're interesting to knit with, a little grabbier than round lantern moons, but less grabby than round brittany birches or clovers. I like them, but if I buy more, it'll probably be in the smaller sizes.