Lots of good detailed advice here, thanks all. My heart says Pro, but my head is telling me my money would be better spent on an i7. It would be the more sensible choice and would do everything I need it to do. I would spec up to the 1tb ssd and then add extra ram myself.
I am in a similar situation, but I decided differently.
I use Lightroom as the primary tool.
I have currently a 6 year old upgradable PC with a 6 core i7 Processor and 16 GB of RAM. I have approx. 150000 RAW photos (growing) in my catalog which is on a separate SSD.
At times I come home from a photo shooting with 1000 to 2000 images.
Importing, rendering standard and 1:1 previews takes hours and editing of photos is slow. I
I think the extra cores on the iMac Pro will help with the tasks. Adobe products will use MultiCore. The support will certainly increase in the future.
I plan to run a Virtual Windows session as well.
I had historically build my own PC. I participated in the C64 and Amiga era (the competition of Apple at the time).
I am no longer interested to spent hours and hours to upgrade my PC and handle the problems my PC’s have giving over time. Motherboard replaced, hard drive replaced, Cooling fans replaced ... Windows is becoming slower and slower with each update ...
So I am ok with an all in one iMac. I believe the new iMac is improved in many areas and not just what is discussed here like Procesessor, RAM, GPU, SSD.
What has not been mentioned the improved AirFlow which first tests indicate it’s very quiet. Improved camera, audio and external connections.
So people might be right that at this time the i7 iMac might be sufficient for what we do.
But for the extra $1300 for a comparable machine, I am getting current technology with a great looking design. I ordered the 10 cores and I am confident I will see performance boost in rendering etc.
In addition even if some of the components are throttled in the iMac Pro, this just means to me that this machine is made to last longer without failure compared to the i7 system. Only time will tell for sure, but I am taking the risk to see if this All In One will last 6 to 7 years without a hiccup.
Summary:
While in the past I was experimental. Now I am just trying to get something that will just work for the next 6 years (3 years covered with Apple Care). In addition I will enjoy it and it will look beautiful!
Recheck your head and you may follow your heart.
Good luck with your decision.