I'll get slated here for a windows build but my home server, which is used for Plex, as well as running various Linux VMs for things like an apache ssl proxy, pihole, etc, is:
i5 4560
16GB ram
6xWD Red Pro 7200RPM
2x Samsung 830 256GB
1x random 120GB mSATA boot SSD.
I have the 830s and the WDs in a Windows Storage spaces tiered, mirrored array. I configured this with server 2016 trial, then installed windows 10 (which can run tiered arrays just not create them because reasons), running ReFS.
I'm not a fan of RAID 5 or 6 or 50/60, the parity calculations make it too slow. With mirroring, I lose 50% of the capacity, but with raid 6 I would be losing 33% of the capacity here. I gain a lot in speed tho.
The tiering really makes a difference. It massively improves the performance. ZFS doesn't really do tiering, although you can use an L2arc cache etc, this is not the same thing and doesn't bring the same benefits.
I'm very happy with the setup!