I've been running a full tower Windows server with a dozen drives for a decade and decided to downsize. This ministack does everything I need at a fraction of the power, noise, and heat.
I use it primarily for Plex but also host a few games servers for buddies. It fits perfectly in my entertainment center.
Spent around $200 on the Mac Mini plus $600 on the drives and enclosures. I'm using SoftRAID for RAID1.
In this case they have some justification for the RAM at least. They use a SoC, not a more typical CPU. And the RAM is available for both graphics and system memory, so for some uses, you could do things on a higher end Mac that is not possible on a typical consumer PC.
Still sucks for people like me though. I really want to switch to a mac Mini for my NAS/home server but I can't justify the upgrade cost to get a useful amount of RAM.