GOG is one of the few steam alternatives I've been inclined to try out. Read more above, but right now, they're offering limited time imports of a limited selection of your steam games into your gog libary. Read above for details. Even if no games in the current lineup are a fit for you, future offerings might be. I think Steam has been less of a PITA about DRM than most companies have been, but DRM is still a useless potential point of failure, so why not get a permanent flawless copy of some of your games at GOG?
@tman, Steam is DRM. Definitely hat's off to KSP if they managed to opt out, but I think GOG deserves some props for creating a 100% DRM-free store.
Steam has also gotten more annoying over the years. Forced game updates before you can play reminds me of microsoft and consoles. I'm not completely sour on Steam (that's probably where I'll get Fallout 4), but where the price is the same, I'm definitely now biased towards GOG.