What would be the difference between buying a game DRM-free on Humble Bundle and buying that same game through GOG?

Depends on the game, most games sold here have some kind of bonus.
up to personal preference I guess.

Well they're different companies and platforms.
That's definitely a difference.
And I'm not sure how good developers/publishers are at keeping their game up-to-date at Humble.

On Humble you get a Steam key...

So that when the devs ditch the DRM Free build you at least still have an up-to-date game

Gog adds the gog installer on top of the game's own setup

I hate when devs do this, Force us to use steam cause they are too lazy to update the DRM Free build on any platform...

I tend to stop supporting devs that do this.

I give credit to blizzard for updating the old DRM free games that don't use blizzard launcher.

From my experience, while GOG gives you an installer, Humble provides .zip files instead. Sometimes they contain an installer as well, but I think most of the times they just contain the games' folder ready to be unpacked. Meaning there probably won't be a proper installation with changing of registry entries, the folder is portable, and if you want to remove the game from your harddrive, you have to delete the folder manually, it won't be listed as installed program in the Control Panel. Whether that's a pro or a con or neither is up to you to decide.

Also, it goes without saying, that you won't be able to use the Galaxy client, if you get it from Humble, but that's probably not really a concern for you. You won't get the same support either, though. If you have issues with the game, GOG support will try to help you directly, and they're often quick about it. Sometimes it may take a few days before you get a reply, but Humble support can take weeks to get back to you, and they will probably just contact or refer you to the original developer, while GOG will try to provide first hand support.

Oh, and I don't think you get notified by Humble if a game gets an updated version. You'll have to check your game library regularly and compare version numbers or dates yourself.

What GoG gives is consistency and support. Humble just perpetuates the monopoly of Steam.

Humble:
Cheap
Rarely update games
DRM free is not as clear cut
Do have games there which are not here (Bioshock, tin man gaming, for example)
90% steam keys

Gog:
Currently drm free
Will push you hard to use client
Pricey, comparatively
Reasonable updates
Occasional bonus things like manuals
Some good freebies not tied to anything

Me, I have virtually exhausted the DRM free from humble and there doesn't appear to be any new drm free coming, all steam keys. Gog is still ok, but the whole client thing is very worrying for the future and there is very little of any interest coming out in months. So I would still advise Gog.

I forgot the last time I bought PC games from Humble Bundle, their DRM-Free installers tend to be outdated for some games (I'm looking at you Crimsonland Developer).

Personally I suggest buying from GOG whenever possible, games are updated much frequently and there's better management overall.

Reserve HB for when a game is not available here.

I think you are over-worrying about Galaxy, but. BUT. I can see why you have a concern and I share it too, just a bit.

Not Directly DRM releated, but the games from GOG are easier to install then Humble Bundle.

I've said it before in other threads like this one: to me the most relevant difference between GOG and Humble is that the latter has a complete hands-off approach to DRM-free builds. As we know, GOG requires the devs to send them the builds, and GOG then (allegedly) tests them and packages them with its own installers. Humble does nothing o the sort: the devs themselves can directly upload whatever they want to Humble customers' libraries. So:

1) GOG versions of games should be more reliable and bug-free than Humble's, even if only because someone has actually bothered to check them.

2) If a DRM-free build is outdated in Humble, it's 100% the dev's fault, and they cannot pull the 'we have to go through hoops and loops to deliver an update' card there.

As a corollary of 2), in time I've learnt to directly contact the dev/pub if anything's wrong with some DRM-free build on Humble (instead of Humble's own support) as it's usually way faster to get a fix or even a reply.

Zip files can be opened and unzipped/extracted using any OS?
Portable folders don't mess or clutter registry?
The installation time is how long unzipping takes and unistallation time is how long it takes to hit the delete key?

These are definetely pro's and should be rather standards than exceptions in software distribution.

Of course, Humble doesn't have any standard in the distribution.
You can have zip files sometimes, sure. Then again you can have rar's or something else. And of course exe's too. Or sometimes exe's inside zip files. Or some more uncommon file formats, like Flash-based games or whatever.

I actually wish they would have zip's (or rar's) for all of their games, which would be consistent and you would know for sure what you are going to get.


And to answer the original question, the difference between GOG and Humble Bundle is that GOG is selling games 24/7, whereas Humble has bundles which appear every now and then, contain a random selection of games which are sold only for a limited time never to appear in the same bundle again.

The "real" Humble Bundles have been always DRM-free, but Humble also sells other kinds of bundles, which may only contain Steam keys or have only few games as DRM-free downloads. Reading the bundle description will tell you what you are paying for. Usually you can choose how much you pay for the bundles as well, although some tier levels have minimum prices and if you want to have Steam keys you need to pay at least one dollar.

Of course, buying from Humble Store is a different story, but the question seemed to be about bundles.

Oh, I remembered something else: If you're interested in buying DLC later on, you should make sure that Humble actually sells them. For example, Humble apparantly doesn't sell the Wildcards DLC for Hand of Fate. You can buy Hand of Fate from Humble, DRM-free + Steam key, but if you want to play the Wildcards DLC later on, you'd have to buy it on Steam and could use it only in combination with your Humble bought Steam version. Or buy another copy of the game + DLC on GOG. It seems you won't be able to get a DRM-free Wildcards DLC for your DRM-free Humble version.