Linux for the moment whilst we work out our contract for Jamf Cloud.

Both macOS and Windows have too much overhead IMO. I can spawn new Linux VMs nearly instantaneously.

Using Windows with Virtual Server for JAMF. I love the ability if things are getting slowed down (and granted that's only happened when I tried to run an inventory report on every iPad, lol), that we can shut down the server, increase the RAM and fire it back up.

Ubuntu boxes on AWS, with RDS for database and an elastic load balancer up front.

RHEL VMs for everything because, as @milesleacy said, easy to spin them up as needed.

K-12 school system with 23 sites with 430 managed Macs behind zscaler web filter and GRE tunnels. Using 1 Mac Mini for Main JSS and 3 Mac Mini's at sites with Mac Labs for file share distribution points (imaging and App installs).
Works very well, just have to be careful with what version of SQL you use. We use community version 5.6 and there is a minor issue with Java security files that we have had to apply a simple fix for.
Other than that, setup on Mac Mini Server is relatively easy and has been reliable.

Ours is all VM Windows Server, it works but I wouldn't call it wonderful...
We do have a Linux support team so we routinely flirt with migration, but it works as it is so we never quite get there.

Windows VM.

All Windows Server 2k12 R2 VMs, because we are mostly a Windows shop on the back-end.

• primary mysql host (beast spec)
• mysql replica
• 5 Tomcat nodes behind a F5 load balancer where SSL terminates at the lb
• soon 3-4 Tomcat nodes in the dmz behind a lb to serve external clients for check-in only (limited access)

This setup will be serving 30k+ Macs globally.

Professional Opinion: Use whatever platform you are most comfortable with, but keep in mind you may want to switch for reasons down the road.

Personal Opinion: Linux every time