I'm just curious, if anyone else has some more info on this one?

I hope we'll receive it too, I bought both the Steam and the GOG release.
The Steam release was cheaper with their fair price, but it lacked the music, so I had to buy the GOG release soon after, which had a higher price.

I wouldn't get my hopes up for a GoG release if I was you. Friend who has it told me the Steam version disables all updates if you run the exe without steam and with internet off, suggesting some sort of DRM protection over them. The Steam page has also an EULA stating

"IN ORDER TO PLAY THE GAME AND/OR ACCESS CERTAIN FEATURES, YOU MAY BE REQUIRED TO HAVE AND MAINTAIN A VALID AND ACTIVE USER ACCOUNT WITH ZENIMAX (“ACCOUNT”). "

Doesn't seem in line with GoG philosophy

CORRECTION: I'll happily admit being wrong on that one https://www.gog.com/forum/quake_series/quake_enhanced_update

If it's anything like the Doom Unity ports you'll need a Bethesda.net account only for online features (multiplayer or downloading official addons). The main game and expansions won't be affected if you don't sign in.