What do you think?

You should focus on finding high quality renders. Yours are not cut out or blended well, and that really detracts from the overall signatures. I think experimenting with some different fonts would be a good idea, too. Something more substantial would look better in the linked sig, in my opinion. Keep at it.

 

You could always try not rendering it, and incorporating the background of the image into your signature. That's what I do most of the time, because I hate rendering and am usually too lazy to search for an image I like already rendered.

RE: advice: the way I would do that is make the canvas bigger than I'd want the signature to look (and choose to have the background transparent, rather than black or white), then build the signature-esque part inside of that, and place the render so that it's completely inside the larger transparent canvas, but poking out of the smaller dolled up "signature". Everything that's transparent when saved as a png will just reflect the forum skin, and the render will appear to be outside.

Does that make sense? It's awfully simple, but I think I described it in a way that sounds needlessly complicated. The main thing would be to make sure you have an extremely well cut and high quality render, or it'll look like complete crap.