I just thought of this: would Indigo Prophecy even run on the desktop I'm gonna build? Specs for my desktop I'm building are: i7-4770K, ASUS Z87 Plus motherboard, Hyper 212 EVO, R9 290X (graphics card), 1 TB WD Black HDD, 16 GB DDR3-1600 RAM, Windows 8 OS. Just thought of this since it is a fairly old game and my PC stopped running old games once. (Or at least that's what I remember it as.)
Well! I think it's quite impossible for any of "their" games to give your PC viruses. Maybe you are using a silly antivirus program that gives you false warnings. It sounds like you never tried it though.
The GoG games would of course be fabulous for your not-so-good laptop.
It just seemed shady to me, like it would give my PC viruses. That's all. But now that you say that, I'm gonna try GoG as well as Steam.
While I could understand that concern with a no-name site, GOG has been around a while now. I've had my account with them for about 5 years, and have had no problems. If you're worried that they will go belly-up, too, you could buy the game, download it, and burn it to a disk or something.