I like the strong graphical expression of #10 but I am not so fond of text logo placement and the plain 2D feeling. Try to place the logo on the right side of the sign, and make text bigger. Is it possible perhaps to merge the sign and the text logo into one? Perhaps replacing the E with the sign. The current layout could be nice to have for a businesss card, but for the web page it isn't the most practical one. I love the strong simplicity about it, but it is a bit to plain as is is now. Perhaps a 3D plane rotation or something?
#15 is much better, but the colros - gray, black are a bit boring. I like the rounded corners of #18, but prefer the bright text. The textfont is a bit to strict - would like to see something more rounded, moderns, sleek.