Overly complicated sigs are a pain in the butt.
Seriously.
Why should I have to try to pick out the two words of text that are actually relevant in a comment by weeding through lines of style tags that render a sig in fancy colors? It's great that users know how to make their stuff all pretty, but I'd prefer if it didn't have to look at a shitton of tags when all I want to read is the comments in edit view. We're an encyclopedia here, not an exercise in design. Simple, clean functionality is best, not hideous bloat. Custom sigs are fine, a couple of links are useful, but fancy formatting is a serious pain in the butt. Please don't use it, for the sake of everyone's sanity.