There are so many good fatties out there,
Surly included. I've had two aluminum (Framed, Mukluk), and I'm now riding a carbon Borealis Yampa. They've all been a lot of fun.
If you're intending to bomb rocky and rooty singletrack then, yes, I agree a fat bike might not be the best choice (unless you can afford something like a Bucksaw). But if your intention is to get out in the woods and explore, a fatty will be excellent.
The bikes you list are different animals. For example, the carbon Muk and the Surly ICT. The former is more trail oriented, the latter more XC and Bikepacking. Decide what you want and go from there. Personally, I would not consider the Farley. Trek is one of the 800 pound gorillas bent on ruining the industry.
Lastly, consider looking used. I started cheap on sale (a barely used bike that was returned because it didn't fit the buyer) to see what I liked, upgraded in a good deal (frameset only that had been owned by a shop employee and was insanely cheap) then sold that Muk for more than I bought the Borealis for. There are SO many people buying fatties on a whim that the used deals can be excellent. You have to know bikes, of course, or know someone who does whose advice you can trust