Pretty cool sigs. I'll try to CnC them.
1 - Colors are off. Background doesn't match the render. The render isn't blended and there isn't any flow or depth. 4/10. Just by looking at it - 6/10
2 - For a no background sig, pretty good. The lighting doesn't make sense, but it looks good. 6/10. Looking - 5/10
3 - Pretty interesting. Your lighting is always the same though. Try not always using the red fuzzy brush. Text throws it off. 6/10. Looking - 6/10
4 - I like this sig. Nice brushes, splatter effect. Though, text still throws it off. 7/10. Looking - 8/10
5 - You use too much red. 4/10. Looking 4/10.
I'll finish the rest later.