Writer's Fallout Shelter

I've written a few stories that either have the main character die or have the antagonist win. I've read a few too.
I think what matters is the plot. Is it believable? If the main character learns something or changes in some way and if the loose ends are wrapped up then, no matter what the plot brings, the ending is solid.
The question I suppose really is:
Is the ending Lazy (a quick and dirty way to wrap up the story) or Logical (Well thought out using all the writer's tools).