Executer: - Money back, no questions asked (first 2 hours of gameplay iirc)
- Bigger Multiplayer base (more exactly THE real multiplayer base)
- More advanced client (driven the industry since its introduction)
- More (or better ALL important) games
- Updates and developer Support
That's some reasons to choose Steam over GOG.
GOG has
- DRM free, or what is left from the principle
- Shoehorned in single player/offline modes so it formally passes the DRM free label.
My point is... those things were (mostly) true before Galaxy. If you chose to use GOG, you must have had good reasons already... GOG / Galaxy is by far still more consumer friendly that Steam is. So it's really doesn't make sense to go back to the more restricted platform. I could see using it in conjuction with Galaxy like darth said, but not abandoning one for the other.
Does Steam allow you to download standalone installers via their client? No
Does Steam try to fix old games before release? No
Does Steam allow pretty much every game to be launched directly from the exe without the client running? No
Does Steam allow you disable updates while online without forcing you to update before playing? No
Does Steam offer an easy to use rollback feature that can be used for nearly every game? No
Does Steam allow you to disable features you don't like? No
All of this is possible in Galaxy though...
I'd also argue that Steam isn't the more advanced client. Not really. Most of the major features Galaxy already supports, only things missing really is trading cards, profiles, and workshop support. But Galaxy is technically more advanced because it's not as old as Steam. Steam made questionable decisions when developing their client (but who can blame them it was like 2003). A lot of that old code still exist though, Steam needs a complete re-write by today's standards.
Just my thoughts, carry on though... don't want to start some big debate. I just see little point in crawling back to Steam due to Galaxy alone. You must of had reasons for picking GOG to begin with, and Galaxy dosn't really change that.