Here in Germany I love the Regia "Meilenweit". And the Regia Soy is great. I do not know it Regia-yarn is available in the USA.
And I love "Fabel" bei garnstudio.com. That is available, I know.
They do not only have colorful / multicolor-versions but also plain colors.
Fabel seems to last really well (people say that made their socks a long time ago and they last). It is really nice to work with. And it is a little more "puffed up", so the stitches become more dense with the same weight yarn.