For the longevity of a product and intuitive design. But it is a matter of opinion, and if you are more comfortable with Windows, then stay with Windows.
If you have one user or 1000's of users (especially using Windows), Windows Server is a no-brainer! The only reason I would suggest going with a Linux server is if you have old hardware (Windows Server is more process intensive than Linux). But, Linux is open-source, so anyone can publish updates/security updates, but on the flip side, malicious people also have full access to Linux's codebase allowing for much easier writing of exploitations/viruses/malware/ransomware.
DHCP Server could be better - we use the router for DHCP Routing
Print Server - not a fan of using the server as a print server since you have to license it. Direct access to printers via IP addresses is a much more efficient way to go
Better backup program - we utilize a third-party program that gives us more flexibility when restoring individual files.
I've carefully reviewed the servers and services currently running on Windows Server 2012, and given the opportunity would renew them as is going forward. There are two systems I currently have in place, one is a very large Linux implementation for a large ecommerce site, and one is a very large backup solution front ended by FTP servers running Linux. Neither are well suited for Windows, but the overall network infrastructure is and will be Windows Server for the foreseeable future.
There are simply too many different parts of Windows Server to make it a cohesive piece of software. While some of the newer features found in Windows Server 2012 and 2016 have nice UIs that are logically laid out, there are enough parts of the system that is still based on old code with clunky UIs and confusing options to make Windows Server a particularly user-friendly experience.
Microsoft's support is hugely wide-ranging from articles online to having to contact them directly for the more serious issues. In recent years when I have contacted them directly, I have found the support o be excellent as I have found myself connected to very knowledgeable people in the field in which I needed the support. The online support available is vast and I tend to find most of the time that there is always someone out there who has had the same issue as me in the past and knows something about how to resolve it! This is the advantage of using industry standard and long-established systems such as Windows Server.
Make sure that you have detailed processes in place for every server instance you plan to install/upgrade, if possible get the base OS loaded and Windows Updates applied ahead of time, and if using a VM take a snapshot prior to installing each role, as well as along the way.
macOS just makes sense to me. Each OS has its pros and cons.. macOS works for me. It's well designed, intuitive, and efficient. But it's not cheap... well, macOS is basically free, but you need the hardware to run it, and the hardware isn't cheap. Pick the right tool for the job and for you. And even though macOS may not be thought of in an enterprise environment, it works remarkably well if configured properly. Tools like DEP and ABM from Apple enable device management and lock them to the company. Use an MDM like Jamf to push policies and packages. Jamf can also manage accounts and authentication. JumpCloud is another great product for account management. Although it might not be all included in the box, with the right knowledge, you can build a robust and versatile enterprise Mac infrastructure. You can even do zero-touch deployment in most cases with the correct setup. And Apple employs engineers to help you get it set up right.
I didn't use any other system which gives the same functionality and I am not aware of any. The full integration between all components and especially the ability to integrate mail via Exchange or even via a hybrid setup with the Ofice365 cloud, including the ability to directly manage the cloud from the server, using Power Shell, is something I didn't see anywhere else.
Because of our Microsoft Campus Agreement, Windows products are fairly affordable for us and that has been a huge blessing. We are considering some Azure cloud options and some of that is covered under our Campus Agreement, making it a nice incentive to start migrating certain apps and functionality to the cloud
I don't have access to our budgets so I cannot give a good answer as far as the impact of ROI on our institution, but if your company can afford it, you cannot go wrong with Windows server. Not having to send your sys admins to Linux or Unix school alone is a big savings as well as not having to train your staff on using a Linux desktop instead of a Windows-based one.
The compatibility with end users of all varieties and platforms will definitely impact your ROI in a positive way. We have Apple users, Android, Windows, and even a few Linux end users on our campus and Windows server works quite well with all of them.
