I haven't read anything outside his Ender or Shadow series, so I can't truthfully say what I think of him as an author. But all the books past Speaker for the Dead and Ender's Shadow are horribly written.
Though the hallmarks of his style still remain clear (character development/relationships and subtle world creation) his story writing became subpar. Each book become increasingly more like a mouthpiece to spout off interesting ideas without getting anywhere. I really think the final three books in the Ender's Game saga would have been more powerful as a single volume.
Like Hunchback I'm not even going to touch any new Ender books, though I will look into his earlier works to see him in his writing prime.