The main difference will be the fact the LE is available a year earlier, and that there are only 500 of them so they will be quite collectable. Other than that, I'd say the Mass Market edition will be superior in production quality, simply because luxuries such as gilded edges etc simply aren't possible with a small run.
I'd suggest you wait for the MM version, if rarity and getting the deck sooner aren't a concern for you.
As for size, finish, backs etc, Kunati and I are a long way from finalising specifics like that for the MM version. All we've really determined is that it will be a 'deluxe' deck. Nice box, gold edges etc.