I have the XT's which have double the tread and have been very happy with them. Havnet let me down yet. Ride smooth on hardpack and do quite well in the mud.
I'm not sure about the DD II but i beleive there similar to the grim reapers.
I've had the reaper for about 6 month now and have nothing bad to say about them.
There an great all around tire real smooth on the road and do great in the mud and sand.
There 8 ply and wear very well. I have 800 miles on them already and the tires are showing very little wear. I think the DD II would be a good choice.
i had the dd 1 years ago anbd they were a great traction tire but wore out fast. maybe the dd'2 are better and if a 8 ply that would help. just check thier web site for sizes an you should be able to tell.