This is a very nice signature It has a nice skyline inside in the text, and has a nice glowing effect (including the center piece). I don't think that there is anything wrong with it, but I think you should make it the size that it is going to be so that people can see what it will look like when it is the size that it will be.
Eww. Just Eww. For a decent text sig you need flow. Not a bunch of single effects that make no sense. If you were going for a "city" theme, I would of chosen an asfault texture and more grungy effects to go with the buildings. You just have fractals pasted+linear dodge. Also don't use the same font over and over again.
Agreed with above, try a different font and see how that looks. Better with the background effects and stuff, but the right hand side white swirl shouldn't be there at all.