If a film that I really like is released in 3D and 4K I'll buy both versions; so that's actually costing me more. If it's not what I regard as a top tier release; but I still want to own it; I'll buy the 3D version only. Of course; I may still pick up the 4K version later second hand or in a deal. A few 4K UHD's have been worth buying i.e. Billy Lynn's Long Half Time Walk, Bladerunner and The Fifth Element. Almost every other UHD 4K disc that I have seen is only a marginal improvement over the BD version. I'm not saying they're not better - they usually are. I've put on UHD's and thought this looks really good. But when I put on the BD; I think that it's nearly as good..Agree on the 3D, looks great, best 3D experience, but, the HDR is even better. If you don't see much difference, good for you, as you don't feal the need to buy 4K Blu-rays. I use VUDU too and I see a good PQ uptick from Blu-ray, depending on movie, as not all are great. If you don't see un upgrade on movies like John Wick 2, The Last Knight, Chappy, Miss Peregrine then your wallet will be much happier than mine )
I have to wholly disagree about HDR being better than 3D. For me; an immersive a/v experience has three principal elements 1: The Image - which I judge in terms of colour accuracy and detail. 2: Depth/Spatial Accuracy 3: Sound.
HDR enhances image quality; but with UHD that is at the cost of removing one of the fundamental components of the a/v experience - depth. Depth is part of the real world and should be part of any form of realistic replication of the world.
If UHD had come along and offered image detail enhancement over Blu-ray; but at the cost of the image being in black and white or lacking sound; I don't think most people would find that acceptable.
For me depth is as important as colour or sound. I'll take a marginally less detailed image and marginally reduced colour accuracy that also includes depth over UHD any day.
I'm not anti 4K/UHD at all. It's just that the format is rather underwhelming on the whole.
One more thing I forgot to add. HDR movies are intended to be watched in pitch black ambient in order to get the full HDR treatment when it comes to specular highlights. The brighter the ambient, the lower the impact of the HDR.
The HDR effect can make it look more HDR-ish, but, it can't add colors, as in the WCG that comes with native HDR movies.
I agree with you about ambient light being the enemy of critical viewing. Everything (HDR or 3D) is enhanced in pitch black viewing conditions.
Of course; the noise and grain that plagues many UHD discs is even more obvious under such conditions...