I currently have a SB8 on the back, which is supposedly quite similar to a Larsen. Experiences similar to others (recreational XC type riding) :-
Tarmac – Ok, but probably not as fast as you would expect
Hardpack – Feels fast
Mud – Not as good as a wider spaced tyre, but can cope with the odd patch of mud
I am using it on the back at the moment, with a Nevegal up front, and i’m happy. I wouldn’t use it in very muddy conditions, and I wouldn’t use it up front unless almost all of a ride was dry. I will probably be using it as my front summer tyre though.