Recent reviews by 大好きだよお前は

The difference Is visible. In some cases there's little to no difference, but other than that it looks fantastic.
Framerate wise I am holding solid 80 fps in 1080p in the city or anywhere in the commonwealth with additional 4k texture mods UgridsToload on 7 and ENB. So GTX 1080 is definitely overkill. 1.9.4 update in itself raised my framerate by 20 fps alone.

Rocking a GTX 1060 6gb and an I7-4790k. Average vram usage is about 4-5 gigs.

I think if your system can handle it and you have that free space. You should get it, and load times are almost the same, maybe a bit longer.