All reports are that LOTR looks about as good as it can without re-rendering the CG at 4K. FOTR’s colors have been fixed and it sounds like the HDR grade isn’t overcooked like a lot of film-based material, which simply looks wrong with eye-searing highlights (in my opinion). Warner’s 4K releases have mostly been spot-on and I expect this one will be no exception.
I watched the extended Blu-rays earlier this year and a viewing once every year or two for epics like this is enough for me, but my 4K copy is supposed to arrive tomorrow, so I’ll probably watch it this weekend. I thought about waiting for the deluxe set, but I’m not interested in The Hobbit (sat through the first and only got about 15 minutes into the second before giving up) and I really wanted Best Buy’s steelbook set, which likely won’t be available in the long term.