On the one hand I like GOG because it has no DRM and has better prices (in my country) than Steam and I have the feeling that on the one hand it follows more the open source philosophy than Steam itself, but Steam has helped enormously to play Windows games on Linux, so I haven’t really made up my mind.
On the one hand I want to buy on Steam for the convenience, but on the other hand I prefer GOG because (in my country) is cheaper. Which platform do you prefer and why?
To give an example, The Binding of Isaac: Rebirth is currently $15 on Steam with regional pricing, but on GOG it’s worth just $6.
I strongly prefer GOG to the point where I often don’t buy games that are not on GOG.
That being said, one reason to buy from Steam is steam workshop. So if I want a lot of mods, I may buy from Steam even when available on GOG.