From HP Z230 manual:
<…> The Linux kernel, with built-in software RAID, provides excellent functionality and performance. It is a good alternative to hardware-based RAID.
It is not a news of course, but (1) I like the wording; (2) it comes from a major enterprise-class server vendor.
There are still a lot of RAID-card fetishists among systems administrators who bash Linux-based NASes (like ones produced by Synology or Netgear) for relying solely on mdadm.