"If the road is icy, 4 part time is fine, otherwise who needs 4wd on the street? My xj had a 242 and I never once had a desire to put it in 4 full time? I think the disco is a horrible idea, swap in a weaker 2 piece shaft, so when it breaks at least you still have 3 wheel drive? I had a spartan up front and it worked great. If road conditions are bad enough you need 4wd, the locker up front won't hurt anything. The locker in the rear however can lead to lots of slideways action."
This may be true for some parts of the country, but here in Montana, there are lots of times when the roads are part icy with other parts bare pavement. The full-time 4WD is perfect for those situations. It's also nice to have 4WD to help get going at traffic lights on hills, from stop signs on hills, etc.
I agree though...putting in a disco axle is a horrible idea.