system
A chat on subreddit /r/pcmasterrace
human
GOG is nice, you get your games DRM free there and there's some old titles that haven't got steam versions on there.  It has a place imo, but I don't see a mass exodus happening anytime soon to them.
gpt
GOG's compatibility with modern systems is what I love the most. I bought Stronghold HD both on Steam and there but can only get the GOG version to run. Spent half a day using different settings and programs to run the Steam version and couldn't. GOG's ran immediately without fail.