I'm going to do it like t'old SOTW judges did it back in the day because I think that every one of these sigs deserves some critique (and there's only a few of them, so I don't have to write a ton).
1. This one has a really good background, but it suffers from the tragic fact that it's REALLY tiny. I don't really get a chance to see pretty details and stuff when it's at that low of a resolution. I don't really care for the light spot near the top of the render's head. I feel like it cheapens the look. Text is a big deal for me and this sig's text is nearly unrecognisable. So, I don't know. A combination of things caused me to not vote for this sig. As much as I <3 Jaden's stuff.
2. While cutting out the render, too large of a soft-eraser was used. That leaves the edges looking too feathery and non-realistic. Next time, try using a smaller harder brush when doing that. This is is much too saturated and it really clashes with the softness of the render. However, I must say that I realllly like the concept for this. I think it was a good idea, but it wasn't done as well as it could be.
3. I told Sev in a thread in Graphics Central that he's getting so much better at making signatures and this is proof. The background is stunning and it gives just the right balance of contrast against the render. Nearly everything in this signature was well put together and that's why it's getting my vote. The only thing that I found less appealing was that the text is so faint. I feel that using a fiery effect on the SC logo would have been so much more awesome.
4. Is that the American flag burning? O.o It's not a bad sig, by any means. But the font of the text doesn't really do it for me and the colours of the sig just..aren't really vibrant and fiery.
5. A ton of awesome things can be done with this render, but the edges of the flames in conjunction with the bright background bring out the grey edges of the render. Something darker would have been better to see and maybe a different font. I see you use that font a lot, Iron Maiden. Time to switch it up
TL;DR I voted for 3.
NEVER! 
