Sorry, but that's utter bullcrap lol.
The render doesn't fit with the background at all. Colorwise at least in my opinion.
The BG (you said it yourself) looks bland and empty so far.
I'm not very fond of the little.. dots or bubbles on there.
Lastly and that isn't really a bad thing but I noticed you put the text at the exact same spot as on your other two sigs. Perhaps try doing something else with it. And I wouldn't use a blue outer glow (at least not with such high opacity) on the text.
But hey, I didn't make sigs in a while so if I were to make one it'd probably look like crap too xD