The text needs to go. THe lighting is too strong, well more like the white in the sig makes it harder to view. When using bright colors there is no need for real increase in lighting and really you should be seeking to increase contrast, which is missing from here. Nice vector work but the color scheme and lighting needs work on. THe composition is rather empty as well. Try incorporating other elements in the sig but if you were to do so I would suggest you put the render off center.