Also their hardware is notoriously buggy. PCIe passthrough especially, google the PCI reset bug if you wanna know more. There is a project called vendor reset on github that reverse engineered the issues and works around them. The author is sure the issue can be fixed by a firmware update to those cards, but although initially AMD engineers showed interest, further attempts at coordinating proper fixes with them failed. Requests for documentation of affected cards were denied. Compare to Intel where you can freely download all the documentation about their GPUs, with registers, internal state, everything you'd need to write a driver from scratch. People want to fix AMD's shit for free but they don't want that.
We recently had calls with NVIDIA, AMD and Intel regarding their enterprise gpu offerings. NVIDIA and Intel were quick to respond and offer a meeting, AMD took forever. Followup questions, even very technical were answered within two days by Intel with concise to the point answers, no bullshit. With AMD they bounced around for two weeks until we got somewhat useful answers.
I really hate NVIDIA, it's a horrible, greedy company with a shitty attitude. I was excited about ryzen. I'm almost an AMD fan boy in the desktop space. I like competition, when the underdog rises from the ashes. But oh boy, AMD GPUs in the server/enterprise space a a clustersuck; buggy hardware, shitty drivers, clueless salesreps. You really have no choice but NVIDIA if you don't want to hire an expert working in getting these cards to work with anything more advanced than having them encode video in hardware or something.
We really hope Intel will deliver.