This is an interesting idea, although the launch selection is very poor--GOG had a humble selection at launch, sure, but it included immensely popular series like Fallout, Descent and Freespace. So far they don't seem to be doing Windows games at all, which vastly reduces their potential library.
Their console/arcade games also leave a lot to be desired--as Delixe noted they don't even support controllers. This may be partly due to using Flash for these games, but if that's the case then that's just one more reason to not use Flash for this purpose.
Catshade: So what are their policies on DRM, regional restriction, and regional pricing?
There's no mention of DRM or copy protection anywhere in their FAQ, unfortunately. The DOSBox bundled with their installer seems to have a different file size for some reason despite not having a customised splash screen or other obvious signs, which possibly indicates they have modified it in some way.
They don't have any Windows games in their selection as far as I can see. DRM on DOSBox and ScummVM games can only go as far as the emulator itself, so in any case you can extract the installer with
7-Zip or the like and shove the files into your own DOSBox or ScummVM without ever running the installer itself. The same works with DOSBox releases on Steam and the like.
As for pricing and availability, the FAQ mentions that you will pay the same price anywhere in the world but does not actually state that games are available in all regions.
Delixe: The seem to be linked with Gametap which is not exactly a glowing reference.
They have provided emulation for GameTap, not the other way around. Their PC games are wrapped with DOSBox or ScummVM so there's not much that can go wrong in that regard beyond maybe a poorly optimised configuration.