|Hello! *sigh* this is just so cliche ;P Nice work!
Technically, this is good. As was mentioned, the composition/cropping could be a little better. I would crop some of the black off the top if nothing else. Having it centered doesn't bother me all that much though since it is such a symmetric flower. The focus looks good to me and you've avoided noise which is really good at iso200 with all that black.
As for the black background... I'm not really sure if it was the best choice or not. I do like how it draws out the black in the center of the flower. It just gives the shot a completely different feel than perhaps a light, pastel bg would. It makes the color really jump out. I think that the lighting probably contributes, and I'm not sure if you did any saturation changes or not. This color is just almost too bold IMO. I'd rather see a lighter background because it would make the flower seem softer and not so "in your face". Of course it's just a difference in taste rather than a right/wrong issue.
This reminds me of some poster-sized pop art that I've seen. It's really very simple and straightforward - emphasizing simple shapes and bold color. In that sense it is a strong, successful image. I personally just like flower shots that are a little softer and more complex - maybe showing more negative space or a vase or another flower or an angle that isn't straight on. However, this pictures reminds me a lot of the third place rose shot so it obviously has its own appeal. Even the close crop on the bottom is the same.
All in all, it's a good picture that I really can't find fault with. This was just a very competitive challenge in general and especially for flower shots.