I fitted 1.9 Landcruisers to the MTB last year.
They worked very, very well. Initially I put them on for a double run along the South Downs Way, which they handled excellently, over the loose flint, grass, tracks and also bits of road - although I did have two punctures on that trip. One was as I turned a corner, and before I could stop, I was riding over Blackthorn trimmings and the other was a tack I picked up (the only punctures I had for the whole of last year come to think of it!).....but to be expected under both circumstances.
I had every intention of changing them back over to the knobbley tyres (I am no regular MTBer, I generally use a touring bike but felt the SDW would be asking too much of it), but I never got around to it. These tyres therefore stayed on this bike, and have been used in all the winter wet roads, muddy tracks and I am pleased with them. I even find that I use the MTB with these tyres on for my main bike at the moment, it has made the bike so versatile and much more "road" friendly - dare I suggest it leaves me wondering if my MTB (a Trek 6700, so nothing special) with these tyres is better for some types of touring than my dedicated 700c touring bike....but shushhh...dont tell anyone! I shall continue to keep them on until they wear out. I reckon you would be very happy with them too