As the owner of a foes mutz I think I can honestly say yes, it could be my only bike. This is mainly because I have not ridden any of my other bikes since getting it. Its spring here btw.
I rarely of ever ride on the road and mostly ride the local rocky, rooty single track. I'm a bigger dude so Im hard on bikes.
I've read some of the responses here and I honestly think it's silly to compare a fully rigid fat bike to a regular fs trail bike. Apples and oranges man. If youre conna compare at least compare rigid to rigid, front suspension to front suspension and fs to fs. I laugh when I see all the comparison videos on youtube where a fattie with a ****ty bluto is put up against an fs trail bike with fox bits front and rear. Of coures the trail bike will do better than the fatty, thats just common sense and a test really shouldn't be needed to come to the obvious conclusion. Comparing a fatty to a road bike is just silly.
So far the mutz has turned out to be my dream bike and I'm not overstating things. Its fairly light compared to some of the steel cranked, 10" travel, triple clamped deals I've owned/own but also seems to handle rough terrain damn good. After I swapped the bluto for a wren 150 things only got better. Its surprisingly lively and loves to jump and can plow down chunk without breaking a sweat. In places where I'd be slowing down to pick through the rocks on a conventional skinny tired bike I just maintain speed and let the fat tires do their thing. If I encounyer a wet marshy or sandy area that would normally necessitate walking the bike I can just keep on truckin.
I honestly can't name one scenario on my trails where I'd choose another bike...
D