I agree with Ryan. Everything that is interesting to look at is pushed out towards the edges and we're left with an awkward void in the centre of the image. However, in saying that this is definitely the best one you've done. Whilst technically it is simple, the lighting and both vibrant and dark blue tones work really well aesthetically. Just work on the composition; I'd also like for you to make a more traditional horizontal sig, plus I'd say you would better luck learning the rule of thirds in that form.