I've had great success with Leupold warranty service. I bought a lightly used GX 5i3 on the bay, used it over a year and it bounced off cart and then wouldn't work over 100 yd distance. I completed form and shipped back - about 4 weeks later a brand new unit arrived - no charge except for my ship to them. They did not ask for any purchase info (receipt, etc.)
That unit got a little wonky in May at a year old - line of sight was perfect, slope was reading down (flat target reading downhill - my pal's Bushnell was always showing less drop than my Leupold. Same deal - I shipped back, new one in shrink wrap package arrives 5 weeks later, no questions asked.
Last tidbit - I picked up a Nikon 20i with slope on the Bay for $100 to have something until mine came back - no comparision between the two, the Nikon's numbers bounced around on slope mode by 5 - 6 yards. Sold it on the Bay for $115 6 weeks later., I would have kept it if it was close in performance.