Dillon has been awesome to me. I bought a used SL900 (shotshell press) on ebay. It arrived with several broken parts, some of them major. For example, a small tab was cracked off the platform, which is the big cast metal to which the shellplate and lots of other pieces mount. The case feed tube was cracked, a return arm was missing, etc. I thought I was SOL thanks to a dishonest ebay seller. I called Dillon to see what those parts would cost to replace and they said, "Nothing! We'll send you whatever you need at no charge." And they did!
Once I had all the parts replaced, I tried to get it running and was having trouble with the primer arm not returning all the way to pick up a new primer. I called Dillon for advice. The tech said it could be any one of three or four things, and to save me the time and frustration of having to test them one at a time, they would just me the parts I'd need to fix all four problems. If the first fix solved it, then I would just keep the other parts as spares. Again -- no charge.
Customer service doesn't get any better than that. I'm a Dillon owner for life. I now have an RL550B, also, and I love them both.