As of late, there is some drift to create hybrid solutions combining filesystem and RAID into a single module,
or a single storage layer, whichever way you call it.
If you have a choice between one of this hybrid filesystems and a traditional RAID controller,
go with the traditional RAID whenever possible.
This includes (but is obviously not limited to)
Microsoft Storage Spaces, which break horrifically.
Supposedly designed to work on lower-end, corner-store-grade hardware, Storage Spaces do not scale that well on the low-end hardware.
Any large (as in more than two drives) setup with Storage Spaces will land you in hot water sooner or later.
- BTRFS, which is just plain not ready for production in its RAID part as of this writing (early 2016).
Illustrations are available en masse in the BTRFS mailing list.
- ZFS, which looks most solid of them all, but still not stable enough on a large pile of low-end hardware.