The canvas looks too wide for me in proportion with the actual render.
Overall, I find the size a little weird but that mustn't be a bad thing :P
I'd always add some kind of borders on my signatures to frame them in a little and underline the tag. (just personal preference)
I guess you didn't add a text on purpose?
It's not bad, don't get me wrong. But that's the flaws that I would see at first glance^^
On a more upbeat note, I like that background and the colors :)