I would like to know too.
I have Kona muslin (by Kauman! Kona Bay is a different brand), and it's very good. It's just that I used to be able to get an even better muslin, which I think was made by SpringMaid, years ago.
I believe both Kona solids (the ones manufactured by Kaufman, not Kona Bay) and Moda Bella solids are broadcloth, which is a slightly different weave than we are used to in quilting cottons. I have purchase Kona solids in black and navy blue, but don't like them as much as others seem to. They are thicker and heavier and, when cut into strips, fray a lot. I am thinking of ordering Moda Bella next time. Although it is also a broadcloth, I have read that it is soft and silky, so I assume it is a lighter weight than Kona broadcloth.
I wonder why solid colors always seem to be broadcloth?