I have done many years ago. I found them great for the very limited bandwidth of use but for most other uses, the width of the tyres and such low gearing meant pretty much useless for everything else unless you downsized the tyres and increased the ratio for the gears.
As they were never meant to be anything other than off road and for fun, on that they are brilliant. You certianly on the Hebrides, have an ideal environment for a fat bike. Sometime after getting my Moonlander, there was a fatbike u.k. forum? which did well. Looking for it now all I can find is that it closed down, moved to facebook then usual forum politics style took over and it's now very fragmented.
I seem to recall a few members in here who were heavily into the fatbike scene. A well known fatbiker in Scotland, Bruce but known in here as coastkid and one in Northumberland (saltyman)