This article on XDA is primarily about why product companies shouldn't use Windows in an NAS (Network Attached Storage) device, but a lot of the reasons they give are true for almost all uses of Windows.

I was recently searching for an NAS in an online shop, and the first two devices that I found were indeed based on Windows, and I rejected them for that reason.

The following is their list of reasons, with my comments.

Windows isn't a lightweight OS

If you own a Windows PC, you are probably aware that the operating system takes up a lot of disc space, and keeps growing with every update. In the past I have had to use an external USB disc to make room for the applications and updates, which made the PC slow and inconvenient to use.

Nowadays, disc storage has become dirt cheap, so this is less of a problem, but the larger the operating system, the slower it is to boot up, and the longer it takes to backup. Also, the larger the operating system, the more RAM you are likely to need to get it to work fast.

Windows is expensive

Even Windows Home Edition is expensive. If you need the Pro version, it becomes exorbitant.

Windows can be less secure

I have written, in this blog, at length about Microsoft's poor security, and their generally cavalier attitude to security, so I don't feel I need to repeat myself on this topic.

Windows isn't designed for servers

Despite the existence of Windows Server operating systems, the fact remains that Windows is not good in this role. Acting as a server was an afterthought; bolted on functionality. This is why virtually every web-server on the Internet runs on Linux, which was designed from the ground up as a server.

Windows doesn't have great remote management

If you want to use Windows in any kind of server role, not just as an NAS server, you will be severely limited by its lack of support for remote management. Again, this functionality was an afterthought.

Windows doesn't play well with more storage drives

As the article points out, anything more complex than a simple file server (with a few disc drives) and a few users will cause Windows to struggle.

Windows will do what it wants, not what you want

This is a constant source of complaints about Windows, for example being forced to update, and then reboot when it is not convenient. Lots of services do not restart automatically after a reboot.

NTFS isn't as good as other file-systems

Windows NTFS file system has a number of issues. Disc fragmentation (a problem which doesn't exist with Linux's EXT4 file system) is just one.

As the article explains, Windows has no built-in support for RAID drives, so if you want RAID storage you will have to buy a dedicated external NAS. Linux has built-in support for RAID (all levels, not just RAID-1).