Alright. Here we go.
First one:
Colors are slightly bland IMO. Maybe a subtle orangish~brown or olive greene Gradient Map would help?
The bottom left corner being empty just doesn't look right to me.
Positive stuff:
The flow is excellent (the only part that bothers me is the part of the C4D in front of the render). The text is well placed, doesn't detract from the render at all, and is simple. The C4D and the render are very high quality. I really like this banner and the style you used to make it. You get a cookie. :3
Second one:
Positive comments first this time
The flow in this is just... wow. Really nice, flashy effects here too. Pretty good work, though I wouldn't say as good as the first one. Once again, high quality elements. KIU.
Constructive criticism:
A few parts surrounding the render do not tickle my fancy. Look to the right of Spidey's head. And where his nose would be, going left. You see that strange "cut" or "slice" in the image? You should have seen that and fixed it before posting. It is easily fixed with some smudging or by covering it up with something subtle. The clipping masked parts are odd looking to me. The part where his arm is on the clipping mask next to his leg is the most odd. The spotty whatchamajiggerz that look like little tiny birds around Spidey's shoulder and his knee are sorta weird. I don't feel that they add anything to the banner.
BTW both banners have excellent depth, and you didn't go overboard with the blur on the background like you have in the past.
Atom Man Sig (on the page before):
Sadly, the theme is Spiderman (the series, not the character, so any character from the series will do), so you did indeed make it for nothing. XD
However, you could just enter your Spiderman sig and I'm sure you'd do fine.
Anyway, on with C+C.
Constructive Criticism:
Hmm. Interesting.
DAT BACKGROUND. Nuff said. XD
I have a thing for sigs with that tone of orange. I just love that color of lighting.
Very pretty background. I'd like to know what you made and what is just an image from the web (I think you smudged the very back of the background). The depth in this sig is absolutely epic.
While I really like the scenery for the background, the other parts I have some issues with.
The render. He's one of the blurriest parts of the sig. I'm not saying he's actually all that blurry, but by comparison, he appears to be. The building next to him is sharper than him. However, the lighting on the render goes perfectly with the background. The sparkles on his palms are a nice touch, but maybe slightly less bright so they don't contradict the shading on the render or the main light source.
The text. Ugh. With this sig, text just drags it down IMO. Plus its color doesn't complement anything in the banner. I also don't like the font for some reason.
Overall the three banners are EXTREMELY great. You're improving your style exponentially. KIU sir.