I can’t speak to the other three versions because I’ve only read parts and not played them so I’ve not cast my vote on the basis of gameplay. Other than to say we really enjoyed playing Adventures in Middle Earth. It’s the product line that really got me hooked on their work.
However whichever version you go with it’s worth picking up the C7 products (they regularly do humble bundles) because their adventures and supplements are great and the art across the whole line is absolutely stunning.
I found them very good at writing Tolkein adjacent material that made you feel relevant to the world Tolkein created without feeling like bit players in the main story. Check it out. Otherwise I echo the suggestion to get the current one.