Think about the stories you love.
Do the characters keep you reading or does the story (by story I mean plot, idea, purpose, or concept)?
CharacterThrough the story, you're developing a relationship with the main character(s). Based on what their personality is, you should, (generally and in most cases) begin to like them, want them to catch a break, root for them to keep going, etc. As soon as you develop the relationship and see their hardships you keep reading. You want to know how your "friend's" life is going to turn out. For some, this is the soul of a book, for others they need a plot that involves more than what just a couple characters can give.
StoryYou've got the concept, plot, idea, intrigue, and suspense playing for this team and that's a lot to handle. Think Inception (I know, movie reference, but you'll get it). The characters tend to come second. For some, this doesn't really matter because the concept is so well played, but for some the humanity element is everything.
So who wins?I don't know. For me, it's a mix. I really need a plot to keep me going but Inception is a movie I'll watch twice in my life. Harry Potter (high concept and awesome characters) well, let's just say I lost count long ago.
Who wins for you? Do you have a strategy for what mix you want in your story? Let me know in the comments.