They made a pc build video which was bad. Lots of bad stuff in it which you shouldn't do when building a pc, sort of stuff which would make common sense not to do. It got ripped to shreds by other YouTubers who did their own videos about it.
Probably still all on YouTube.
I've been using an XU4 for a number of years. Not used it as a server but it works great as a client. I'm sure it would with excellent as a server. I've had Ubuntu, tried Android, and currently running Batocera for gaming.
I like that it has an SD slot like a Pi but also a storage module which plugs onto the board which is much faster. I can boot from one or the other by flicking a switch on the board.
Only draw back is that it doesn't have onboard WiFi or Bluetooth and limited USB ports. I had to use a powered USB hub then find a PSU with a step down inverter to power it all, making it bigger than a small board. I'd still highly recommend it though.