I have mixed feelings about this purchase. I recently bought the sapphire edition bluray of this film and loved it, it has great picture quality (despite the intended grittiness) and a brilliant 5.1 surround mix. But having hopped on the Dolby Atmos/DTS:X/4K/HDR train fairly early, i saw this pre-order and instantly bought it.
After watching this on my 50" Samsung KU6500, with 5.2.4 surround (Denon AVR-X4300H) i was definitely impressed. The grittiness is still present and i understand its artistic intention, but when the grittiness is gone.......WOW. Fine detail is phenomenal on close ups of faces, uniforms, and helmets. You can LITERALLY see every pore on their faces (on closeups), textures of fabric, and the small imperfections on the helmets. While my TV doesn't have all the hardware to take advantage of the HDR10/Dolby Vision encode (only 8-bit panel without WCG) it does afford a small improvement over SDR, and i definitely noticed. The palette is very neutral, but the greens of fields and hills really popped as well as blue sky. I would say the video is a fine improvement over the bluray.
The Dolby Atmos was also amazing, but was it leaps and bounds better than the 5.1? I dont think so. I have my bedroom home theater setup as close to dolby specifications as i can, and while my speakers arent KEF or Klipshe (base speakers and subs are onkyo from a mid-range HTiB and heights are Micca COVO-S) ive been very happy with their performance. The original 5.1 mix was mindblowing (expecially the D-day scene) with Dolby Surround upmixing. The bass was so realistic and chest shaking and the sound stage was so expansive. The Atmos mix is a good improvement. The D-day scene was indeed impressive, but i wasn't hearing super precise object placement of bullets and such. The height channels indeed add a level of atmosphere throughout the entire film, but I wasn't blown away by discrete effects. (surprisingly planes flying over sounded more convincing with the upmixed 5.1 than the atmos).
Overall, the 4K transfer is dazzling when the camera stops to focus on the characters, and the Atmos mix is the best SPR has ever sounded. But if youre not outfitted with 4K yet (and wont be for a while) and are only looking forward to the Atmos track, Id stick with the bluray copy.