First :
The BG is ok although a bit repetative, i think this sig is one of your best but the render needs blending, add a gaussian and motion blur to the render

Second:
The BG is sort of odd and doesn't match the renders, the text is ok though, but the emboss could be turned down.

third:
Its not bad but its not good, the text is hard to read, the render is see through but the BG is ok

Fourth:
Definatly your best so far, just fix the outer glow on the text

Fifth:
Change the text and blend the render and i say it would be your second best, looks quite nice good job

Sixth:
Has no border, render is pixelly and doesnt match the BG and the text is hard to read


Overall good job and i can see you improving Just keep it up