Nothing specific to Microsoft server functions, mostly looking to evaluate it as a platform to run custom server programs on.
Core seems like a solution to a problem that isn't there. Unix was designed bottom up to not have a GUI, and grafted the gui on top. Windows Core just the opposite, they've chopped the gui off. How many utilities assume there's a GUI available on windows? It'd bet pretty much all of them.
So you're building a custom system, restricting yourself to custom software or a limited set of commercial software. You've got to be building a decent quantity of them to even be looking at core. At that point, what are you getting from MS that you're not getting from Linux for free?