Complaints about its working: NONE.
I moved my 6 TB "Games" HDD from one PC to my newest PC i just had assembled. I expected troubles, but none happend. For safety, i installed Steam on the new PC, onto the old installation folder on the new drive.There was an initial hiccup from Steam like "whuh?!" But it settled quickly. I started launching 3D benchmark, that program stumbled initially, but in the end it ran fine.
Fresh boot, next day. I started a random game from the list, and it immediately launched as it would normally do on the old PC. Nice!
Verdict: Steam understands what i was doing, and what i probaly wanted: Moving an old hdd containing Steam and its library full of games to another pc that i just built.
Origin as a games library, launcher.
Complaints about its working: this program is such crap it always gets on my nerves. After moving the HDD to the new computer, i had to reinstall it at least 20 times, redownload all my games and DLC's 5 or 6 times. Unexplainable errors keep popping up. I'm so mad right now i can't talk!
and probably not in the foreseeable future!