As stated in the title, this review is for the black-cased '4K Ultra HD' version of 'Deadpool' starring Ryan Reynolds:
Although it costs an extra 10 bucks to purchase, the fact that it comes with the regular 1080p Blu-ray + the newer 4K-UHD versions (on two separate discs) is, in my case at least, a better choice because I plan on eventually upgrading to a 4K TV + Blu-ray player next Christmas. And so, once I do that, I'll have this movie ready to go, so to speak.
As far as the movie itself is concerned, it isn't for everyone, but I personally love it. Deadpool proves flat-out that an R-rated superhero movie can soar at the box office and smash expectations if done right.
Contrary to some 4K UHD Blu-ray releases available for purchase, the 4K version of Deadpool is based on a master which has not been upscaled from a lower resolution. For example, 'The Martian' 4K UHD Blu-ray is apparently sourced from a 2K master and upscaled to 4K, which, is a huge ripoff in my opinion.
Deadpool also features an upgraded color profile which is part of the reason why people would want to upgrade from 1080p, but I'm not certain that this is the case for upscaled 4K UHD movies such as The Martian.
I had a chance to test and compare the 4K version to the regular 1080p version, and the former looks phenomenal, with far more color and definition devoid of banding and post-processing artifacts.
TLDR: Buy this release if you're looking for a reference quality 4K UHD movie, cheerio!