I only own one Ultra HD Blu-ray at the moment.
Wonder Woman wonder1.jpg wonder2.jpg
Originally, I was more interested in the (beautiful) steelbook than in the UHD Blu-ray, but... you know... there's Christmas time and pressies and all that jazz...
Prometheus (one of the very few films of the 2010s to genuinely impress me) is already on its way, and I'm fairly sure I'll have suitable 4K equipment by the end of the year.
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How about you? Have you already gone 4K, are you planning to do so, or aren't you interested at all?*
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SPOILER:
This is the chance of a lifetime for Dem.
He could jump a whole format generation and move from DVD (or is it still VHS...) to UHD Blu-ray.