It's sunday, today, over here, at least for now (Portugal, GMT+0). I know Steam has the slight advantage of "convenience". Steam is more convenient than GOG because it's immediate, and in this day and age I can understand why so many people prefer to go with that. Still, you have to ask yourself "at what cost"?
Steam may seem more "user/consumer-friendly", at first sight, because they immediatly have patches available and update your games right off the bat, as long as you're connected to the internet and have their client running. This is a good thing for most users. At GOG, they take a bit more time because it isn't automated like Steam's patching service -- on Steam, it's all up to the devs and publishers of the game, as soon as they have a patch, they upload it and it's all automated, machines and servers and all that tech do all the job (Steam is a behemoth of the video game industry, with the millions of consumers they have, it wouldn't be possible to have this system workin in any other way) --, GOG has *actual* people testing the patches the developers send them, then wrapping them in the sweet and easy-to-use GOG installers, then uploading them. It's more morose than Steam's way of doing things, but you also get that sense of security that comes from the fact that you know actual people tested it and therefore it's more likely to work.
Plus, like others have said before me, GOG gives you a fair-price policy, making buying games on GOG cheaper than on Steam, for people like me, they offer you more bang for your buck, with exclusive goodies absolutely free of charge (on most games), their support actually works and it's usually stellar, they have a refund policy that has been tried and works flawlessly, when you buy the games you're indeed buying them, not *renting a service in order to play them via a semi-DRM-always-online-client*, it's ALL completely DRM-free and it all works offline, with no need for activation or checking of any kind. Obviously, it's a little sad that because of GOG being a smaller company than Steam we get these delays and sometimes we are treated as second-rate customers by the devs and publishers of the games, but what you get in return more than makes up for that, at least in my opinion.
There's also GOG's proprietary (fully DRM-free -- and optional) client, GOG Galaxy, in the works, for those who would prefer a more immediate experience, without having to manually download and apply patches to their installed GOG games, and offering full online experience with cross-platform support (if you buy a game on GOG you can theoretically play it online with people who bought the same game on Steam, when using the GOG Galaxy client). Stil, from the looks of it, Galaxy is still far from its release, as it's still in alpha phase, I think. But GOG is definitely working on it, because, unlike Steam, they actually care about their customers and they want to provide us with all the services they can think of, without ceasing to be the DRM-free store they have become known to be.
I don't care if Steam has a more immediate patching service, I would have still bought Grim Fandango here. I know the patches will come all the same, even if they take a little longer to be released. Oh, and since the fix doesn't address the ridiculous OpenGL 3.3. requirement (probably no fix ever will get rid of that absurd requirement), I'm still not able to play it, and my Grim Fandango Remastered will remain there, sitting proudly on my GOG digital shelf, until the day I manage to get the money to buy a computer that supports said OpenGL version. Which isn't going to be anytime soon.
