I'm afraid you're not gonna win, because it's lazy and unappealing. I just don't see anything interesting or good here. I would like to say something good about this, but really, it looks more like half-finished design.
When something is simple, it also has to be balanced, and your design isn't. But when I look at 99design page, it's not your entirely your fault, because their design style is also quite bad. It's also kinda silly when I look on all those concepts, they look all the same. It will be a complete lottery.
I didn't wanted to upset you. I just presented my realistic look on this - you don't have to agree with me, and you don't have to thank me for that. I beleive that you shoud tell your opinion, when you don't mean to hurt anyone, and it doesn't matter how negative it is.