I'm asking for two reasons here.
1) They have games available which aren't on GOG, such as Shadow Warrior and Terminal Velocity
2) Their downloads seem to be inferior. There's no chance to download again at a later date, and the releases aren't as complete as they would be on GOG. Shadow Warrior doesn't include the soundtrack as far as I can see and Terminal Velocity doesn't include any of the CDROM content like the video files....
So I'm guessing either GOG will be able to provide more games from them, or 3D Realms will withdraw their license and we'll lose the existing games, or the status quo will remain. Any ideas which guys?