As my wife as allowed me to devote some of our leftover disposable income on Tolkien books, I am trying to add one single Silmarillion to add some more beef to my humble, but a growing collection.

If I am looking for the rarity with the ability to hold its value (or be able to see increase in its market value) in the long-term, what would be the choice between the Uncorrected Proof (Houghton M), Salesman Dummy, or Methuen bound copy? I understand that good condition Unc. Proof sold for around $250-280. Does it make sense if the Very Good condition one sells for $700-800? If so, I see that Methuen bound one has been selling for $600-700 while Salesman Dummy has been selling for $400-500. Would I be better off in the longterm if I were to choose Uncorrected Proof although i have to pay additional $100? I need help!