I play it exclusively single player, or a few times with my GF so far. I have…check steam 309 hours in it so far.
Its an amazing experience - Its a world ripe with lore, and you can almost feel the heat in the desert, the humidity in the swamp, and the cold of the frozen north.
The combat is great, but rather gory and over the top - Something I don’t enjoy normally, but I got over it. (Obviously).
But what REALLY shines here, besides the rather vast world to explore, is the building system. You can build ANYTHING - Simply anything. The basic building blocks are a square and a triangle - from that, you can build round towers, and whatever your imagination lets you dream up.
One thing I might change if I were you, is the amount of harvest materials you get, once you start harvesting. I use the game mostly as a chill out experience, just having fun, and harvesting is part of that, but I think you may have less patience for that, so increasing that, decreased the amount of trees you have to fell and so on.
Anyways - I hope you try it out, and let us know your experiences in it! Also, I would be happy to join up if you think that could be fun some day :-)
All the building below are by me. (Edit - not the massive hand with the two towers.).