Thanks for the submissions. We like the shadowing and the dynamic approach to the positioning of the first O. We think the "up" needs to be more emphasized than the "pop" in the logo. Also we would be interested in seeing variations of #4 in different fonts and color schemes. Also, with respect to shadowing, we think the "up" is better suited for 3D while the "pop" remains in 2D.
Thanks,
Zaahir