Its a great little box. I have 2 or three cameras recording 24x7, a large chuck of the spinners is a Samba share, and Webmin tells me that I'm usually at 10-20% cpu and 25% memory.
I've got an SSD connected to USB also, and it really makes the spinners feel slow ( WD Red Pros ) but that's mostly because they spend a lot of time idle and the first access is delayed.
Of course it isn't perfect. It holds on to dust a bit too well, and it isn't super easy to connect another USB device once you get it all dressed in place. I don't use the screen. I did at first, but I'm not black-belt level at managing HDMI devices and it doesn't present as much value as the light pollution it causes.
The RockPro64 would probably best it in most tests, but I already had the Cloudshell.
I have dreams of incorporating it into an all-ARM Linux domain classroom.