From the standpoint of someone experienced in graphic design: I like it. Its pretty original. However I can't get over the feeling that its missing something. For a clan banner, I would expect something a bit more gritty. adding a bit of texture could do wonders. I would recommend some gradients or shadows on the ghost to make it a bit more realistic. Perhaps a bit of fading opacity on the marathon logo. It would add a bit to it. And maybe even a bit more of an illumination coming off of the ghost's projection, to make it pop. Its just my opinion however. Theres always room for improvement. Even so, its a very unique and original design, I enjoy it quite a lot.