Drobo - Best Disks to Use

I have a Drobo 5D. I am upgrading the disks. What are the fastest, most reliable disks to use. I use it for storage, backup and video playback. I currently use WD Black, but would NAS or DataCenter disks be better?

It would be best to provide your unit’s hard drive compatibility requirements. Otherwise we could suggest hard drives that may not be supported or compatible with your unit.

What’s the maximum supported RPM?
Which SATA mode does it support?
What’s the unit sleep behavior?
How does it manage hard drive heat dispersal?

Drobo seems to insinuate their 5D range as hardware agnostic according to their website http://www.drobo.com/storage-products/choose-drive/
They seem to support the Blue, Black, Red, Green, Purple, Re, Se line of products.
Just upgrade to latest firmware as it adds support for AF (4K Native) units and 64TB LUN.