Most of the reports I have read, on a few of the Fora, have always been complimentary about the SD-45 loco. I wished, on more than one occasion, that I could have one here but it is a little too large for my small railroad.
There will always be the rogue model, as with anything that is man-made. But if you buy new then you should have no issue as Aristo have a good warranty for their new products.
Regarding rogue items: a friend of mine in Wisconsin recently bought a new truck in the cash for clunkers scheme So far, in about three months, he has had to have a new drive shaft and shock absorbers.. He doesn't use the truck for off-road purposes; just drives about 30 miles along ordinary roads and an Interstate to get to and from work each work day.