At least one first impressions review is out:
And it looks like a serious system but the reports of it not being for most people look to be true. I spec'd one out with a setup that seemed like the minimum to at least take advantage of its' abilities. And it's just over 12k, you can't get an iMac Pro with the same exact setup but with one that's close it's around 8k and you get that 5k display.
This seems to be a very photographer heavy place and for that kinda workload I don't know how much either of these computers are needed (video is another story though). Looking just on the Apple side the iMac 5k has an 8 core processor which is faster for single core workloads that still exist in PS/LR and is still respectable for multicore work. Even the MacBook Pro is no slouch right now with its' 8 core setup and improved cooling/upgraded GPU.
Then there's the non-Apple side, in the video he talks about how fast the SSD is but it's slower than Samsung's PCI-E 3.0 drives and way behind the 4.0 ones that work with AMD's new chips. I just configured a 16 core Ryzen system from Origin and it would have a faster CPU, more RAM, faster disks (though split between 2 2tb drives one being 4.0) and a faster GPU (less vRAM but with AI cores that help in certain Adobe photo applications). It costs about 4k, it's a very different class of machine but that's more my point. Since the Mac Pro was announced that level of performance has come down to the consumer level of chips. So while it's super high end spec has a real audience the designers/photographers who used to buy Mac Pros just don't need to anymore for the most part. And the kinds workloads that could benefit greatly is shrinking as processing power on the consumer end keeps going up at a fast rate.