I first bought a SDB 12 years ago and had the thing paid for in savings over store bought in about 9 months. After 15,000 rounds I sent the SDB in for a check up. Dillon went through the SDB and replaced several parts that were JUST starting to show some wear. Cost... no charge. I've since upgraded to a 650XL and called Dillon twice, once for missing locator pins for a second caliber, and once for a broken indexer ring. Both times the rep at Dillon had the part set for shipping within seconds and I received it within 2 days.
Great people to deal with. Drop by their place at the north end of Scottsdale airport, Scottsdale AZ and get the cook's tour. Heck, if Mike Dillon is around he might give you a look into his aircraft hangar at the back. He's got some REALLY COOL toys.