Like pretty much every technology which makes tech more convenient, Steam Link has its own issues. MP3s and CDs reduce audio quality, DVDs and Blu-ray reduce video quality. Steam Link introduces lag and reduces AV quality.
If you can't accept these things, it's possible the product isn't for you.
Personally I love it - I have two in the house, and have recently started using an iPad with Moonlight (which for this discussion may as well be the same thing). All four with my Steam Controller (with the iPad I'm lucky enough that the controller is close enough to the PC). It's liberating being able to play the same library anywhere.