3 votesBert commented
Deployment isn't really the main issue - deployment is easy - it's the monthly-or-so patching servers (particularly WS2016).
The two main issues being:
1. It takes a while to install an update (not download, but INSTALL) and then;
2. During restart the amount of time the server sits at the blue screen that says Getting Windows Ready... prior to the reboot.
Both physical and VM servers are affected. Even when you patch monthly (so have less cumulative update delta to apply) it can still take forever.
It's not good when your web or email server is down for 30-45mins.