I don't really like rating sigs, so is it alright if i give you a bit of CnC?
CnC :
The first is very bright. Try adjusting the brightness and contrast to make it darker.
The second one is over blended. Blending is needed, but you also want the focal point (render) to stand out.
The third one is way to choppy. Did you render it yourself? If so did you use the pen tool to render it? If you need a tutorial on rendering i might be able to supply you with one, otherwise just stick to pre cut renders from
www.planetrenders.net
The fourth one is your best. Great blending, however the only problem is the text. Look at the tutorial section. God posted a tutorial on text.
The fifth one is alright, but the right side ruins the sig. it looks as though a c4d was just placed there to fill up space.
The sixth one is actually quite good. The blending is decent, but you can still work on it. The text needs work.
Remember. Simple fonts are better than fancy fonts. Besides that, i think you're doing a good job.