How Do You Like It Now, Gentlemen? (1950)

That said, I can understand someone objecting strongly enough to his themes to not enjoy his novels as literature. (The same could be said of Fitzgerald in the same general timeframe.)

But I have trouble seeing how any of that translates into an argument for poor writing unless the lack of overly ornamental writing be considered a flaw.

  His briefcase was lying open on a chair near the desk, and the manuscript pages
  were protruding from it; someone seemed to have stuffed them into the
  briefcase without much care. Hemingway told me that he had been cutting the
  manuscript. “The test of a book is how much good stuff you can throw away,”
  he said.
  
  “When I’m writing it, I’m just as proud as a goddam lion. I use the oldest words
  in the English language. People think I’m an ignorant bastard who doesn’t
  know the ten-dollar words. I know the ten-dollar words. There are older
  and better words which if you arrange them in the proper combination you make
  it stick. Remember, anybody who pulls his erudition or education on you hasn’t any.
  
  Also, daughter, remember that I never carried Teddy bears to bed with me
  since I was four. Now, with seventy-eight-year-old grandmothers taking
  advantage of loopholes in the G.I. Bill of Rights whereby a gold-star mother can 
  receive her son’s education, I thought of establishing a scholarship and sending
  myself to Harvard, because my Aunt Arabelle has always felt very bad that
  I am the only Hemingway boy that never went to college. But I have been so
  busy I have not got around to it. I only went to high school and a couple
  of military cram courses, and never took French.
  
  I began to learn to read French by reading the A.P. story in the French paper
  after reading the American A.P. story, and finally learned to read it by
  reading accounts of things I had seen—les événements sportifs—and from
  that and les crimes it was only a jump to Dr. de Maupassant, who wrote
  about things I had seen or could understand. Dumas, Daudet, Stendhal, who
  when I read him I knew that was the way I wanted to be able to write. Mr. Flaubert,
  who always threw them perfectly straight, hard, high, and inside. Then Mr. Baudelaire,
  that I learned my knuckle ball from, and Mr. Rimbaud, who never threw a fast ball
  in his life. Mr. Gide and Mr. Valéry I couldn’t learn from. I think Mr. Valéry
  was too smart for me. Like Jack Britton and Benny Leonard.”

He is himself, also, as real life characters go, one of the greatest and most interesting I've ever had the chance to read about. What an eccentric and alcoholic lifestyle.

I could see not liking being forced to read his work though. Like the author of As I Lay Dieing which was itself a tough read, I really needed the time and mood to truly enjoy it.