I'm using loads of refurbed 12G SAS drives in my server - 24x 6TB in fact and they are awesome. Connected via a 36 port multiplier card and controlled by a cheap Avago 9364 12G SAS controller.
Also have a stack of refurbed 1TB 6G SAS 2.5" drives in my other server. They're all working very well and also run cooler than the 3.5" drives.
ZFS mirror across the lot in each box.
Well yeah, there just tested and error free. Plus lift the skirt and blow the cobwebs out. Lol.