The Contest Challenge

On the good side, it looks like they both have pretty wide open prompts, from what I can tell, so that's encouraging. Fantasy Firsts has fewer words required, but it only allows the 1st chapter, which might be harder for you if you are doing your story in a series of short stories or diary entries. But Long, Long, Long, which may work better for that plan, is longer, so I guess pick your poison.

When you're grumbling and griping, remember that during April when everything is a poetry contest, there are those who complain to me about that as well. "But I don't write poetry." Well, it probably won't kill you to try. You could write something where you murder me.