Horrible. I didn’t even get to play the game yet, and I can already say that much.
I’ve been staring at the installer’s screen for no less than five hours now – I’m positive that in this time I could torrent Windows 8.1, burn it on a bluray or DVD, completely format my entire hard drive and finish installing Windows. Seriously, if you can’t provide a normal bandwidth for downloads (and this 4 gigabyte thing here at the 70% mark, which is about the third download in the process by the way, is downloading at a mighty 200 kB/s), then just outsource it. Include a limited-functionality torrent client in the installer and make the users download from each other. It’s not such great magic – it’s been done before (sadly, googling “torrent based installer” doesn’t return any relevant results so I can’t provide any actual examples, but I remember such).