See my recommended Macs for photographers and similar higher-end users.
Ordered with 8GB memory, I’ll be testing it with 64GB and 128GB of OWC memory.
Because the Adobe Camera Raw Enhance Details feature uses the GPU intensively, I’ve selected the top-end configuration with the AMD Radeon Vega 48 GPU. See Adobe Camera Raw Enhance Details Feature: Integrated into my Workflow... How Much Does it Use the GPU?. Currently on the 2017 iMac 5K, it takes about 5.5 seconds per 45 megapixel raw file, and 22 seconds for a HighRes 187 megapixel file. Whether the Vega 48 GPU is worth the cost remains to be seen, but at this point, I advise it for photographers since the Enhance Details feature is the best raw conversion feature in years.