I changed from PC to Mac, and this NAS is now significantly faster than on PC.
I was using a Lenovo X1 Carbon with Windows 10 connected over gigabit to the NAS. I use the NAS for photos accessed through Lightroom primarily. The photos are DNG.
My transfer speed was typically 40MB/sec write to the NAS. I have two drives in the NAS, both Seagate 2TB 5400rpm.
On PC, operations with lots of small files, or reading from many directories was slow.
On the Mac, I've connected using AFP rather than SMB, and the speed difference is like night and day. I'm super impressed.
The downside is that OSX has some funny issues where it doesn't resume connections to a NAS share as effectively as PC. This isn't a showstopper, just a bit annoying, though there are posts on the internets about how to improve that situation.
Just to share in case anyone is unhappy with this NAS, save yourself the money buying a fast Asustor or Qnap, and put that into getting a Mac