I like the font treatment on Entry #18. And I like the color in the elipse shapes. Go ahead and remove the tagline. I'm not sure it's needed. I like how the abstract elipse shapes, but I feel like it looks like a hat. Could you possibly change what is around the diamond? Maybe use some flourishes around the diamond and still have lines coming out the right and left side.
Could I see a version of yours with the "O" as a diamond ring? Maybe not so literal but somewhat abstract?
Great start, I hope to see more.