I've got 3,500 on my 04 500SS ADR. Have not had a single issue. Replaced the belt at 2,800, did the sliders at 3,100, and the carbides at 2,400. Sled starts right up, cold, hot, whenever, and all the power I remember when new/broken in is still there.
I did ride my buddies new/350 mile Adrenaline/SC10-III and his rear end felt way smoother than mine/identical preload setting, so I think I'm due for some new shocks out back. I do grease my rear end every 500 miles or so. Other than that it has been the epitome of reliable.