Niggles: Having to install and use Steam is DRM in a good number of eyes though.Just wanted to point that out.
Matruchus: Well its just the way you look at it. I personally use steam only for games I know will never come to gog. And personally gog downloader is drm for me so its just each persons perception.
GOG offers downloadable files that you can store forever on your harddrive, requiring no client to ever install them.
GOG can shutdown tomorrow and I can still play and install my games on a virtual machine 50 years from now.
This won't be possible with Steam, as Steam will eventually cease to exist, or cease to be compatible.
Hence Steam is a form of DRM, and GOG is not.