>>361456505
Bought the device: Thu Jun 04 16:41:19 2015
got an email from valvesoftware regarding Steam Hardware Pre-Purchase - Mac Software Issues Wed, Oct 21, 2015, 1:24 AM: 

We greatly appreciate your early pre-purchase of the first Steam hardware units.
Unfortunately, there are some temporary software issues that prevent the hardware from functioning with Macs. We expect these problems to be resolved as we update firmware and drivers over the next few weeks. 
The Steam Link currently doesn't stream from Macs. An upcoming update will add full support for streaming audio, video, and controller input.
The Steam Controller doesn't currently support gamepad emulation on Macs. If you opt into the Steam Beta client, keyboard/mouse emulation will be functional. We expect gamepad emulation to become functional within a few weeks.
We want to apologize for the delays in providing full functionality for the Mac platform. We're doing everything we can to resolve the issues. For the latest fixes and functionality, we recommend that you opt in to the Steam client beta.
We've added the Valve Complete Pack to your Steam account as a gift from Valve. This will give you all of Valve's games (past, present and future) free of charge. You can still choose to refund your Steam Controller and/or Steam Link (refund instructions below), but the Valve games are yours to keep.