Steam Link 6 mouths later...

The only devices the Steam Link can be compared to are android TV boxes. The box itself isn't too much bigger than a few packs of cards and runs silently. The Steam Link software runs a custom Linux firmware based on kernel 3.8 and glibc 2.19. First Steam Link review here.

The Steam Link interface is very simple. It boots by default into "Big Picture Mode" Again a very simple interface, especially who want a Netflix like experience. Even months later I cannot speak highly enough of how well games stream to this box. At the time of this review, I am working on Tomb Raider GOTY Edition (2013), and it streams in 50 FPS at 1080p on my 37" LED HDTV.

As you can see below, I do not have flagship PC, in fact, it is pretty mediocre, and middle to lower end of the road, and the Steam link works great. Feral Interactive released Tomb Raider on Linux with support for the open source display driver called Mesa. For those who don't know Mesa is an open source collection of 3D graphics libraries. It is geared towards 3D computer graphics, hardware-accelerated 3D rendering and general-purpose computing on graphics processing units (GPGPU). Mesa can be used in many environments from complete hardware acceleration for modern graphics processing units to traditional software emulation.

My host computer build:

OS : Kubuntu 18.04 LTS+Steam Client (1.0.0.54)
CPU: Advanced Micro Devices RYZEN 3 1200 4-Core 3.1 GHz (3.4 GHz Turbo)
GPU: Sapphire Radeon PULSE RX 560 4GB video card [AMD/ATI] Baffin [Polaris11]
RAM: Patriot Viper Elite 8GB (2 x 4GB) DDR4 2400MHz  (PVE48G240C5KRD)
MOTHERBOARD: ASRock AB350M Pro4 BIOS 3.40 (2018/1/10) 
OS STORAGE:  Intel 545s Series 2.5" 256GB (SSDSC2K W256G8X1)
Secondary STORAGE: WB Blue 1TB 7200 RPM (WD10EZEX)
GUI: KDE 5.12.4
Display Server: X.Org (1.19.6)
Driver: Mesa 3D 18.0.0 (Vulkan 1.0.57)

Game: Tomb Raider

Resolution 1920x1080
Motion Blur ON
Screen Effects ON
Texture Quality ULTRA
Texture Filter TRILINEAR
Hair Quality NULL
Antialiasing disabled
Shadows NORMAL
Shadow Resolution NORMAL
Level of details ULTRA
Reflections HIGH
Depth of Field NORMAL
SSAO NORMAL
Post processing ON
Tessellation NULL
High Precision OFF

It should also be noted that the Steam Link has a fast ethernet port or a 100 Mbps port as opposed to a gigabit port (1000 Mbps) which is up to ten times faster.I'm using a powerline ethernet adapter for my connection, which has slightly higher latency but less variance than my Netgear Nighthawk 2600AC. Input lag doesn't really seem to exist 90% of the time. I have only had a dropped connection a handful of times despite using it for hours at a time. You can choose three options for streaming quality: quick, balanced, or beautiful. Quick will ensure you get a clear image without stutter. Beautiful will give you a high-quality image, but if your connection isn't fast enough it may stutter. Balanced tries to give you a pretty picture without stutter. Most of the time I have chosen Beautiful when connected hardwired and Balanced connected wirelesses. In both cases, the picture quality is perfectly fine. I've been able to play without any noticeable degradation in graphics quality.

RECOMMENDED: Nvidia 1000 series graphics cards for Steam Linux gaming.

Note: Steam Link devices will only boot with a kernel signed by Valve. If you attempt to replace the kernel with an unsigned binary you will void your warranty and render your Steam Link unbootable.