I used GOG much more when they were the only ones in town releasing old games, especially DOS games, that actually ran on modern systems. Steam has a lot of what I wasn't able to get anywhere but GOG now; many are even updated graphically or on new engines because certain old games are in vogue now. This isn't Steam or GOG's fault though... If anyone can be blamed, I'd blame Nightdive for making kick-ass source ports and not having them available on GOG.