I recently had to deal with OKC with a warranty issue and I sent one e-mail with a brief description of the issue and sent it in. I had my brand new replacement in under 10 days. I had an OKC Rat 1 plain edge, that did not open as smoothly as a second one I bought with a combo edge. I really didnt realize the first one was off until I compared it to the second one. I sent in the e-mail to ask about it and the rest is history.
I own both knives you are asking about and I think the warranty advantage ESSE usually gets did not apply in this particular case. As far as which of my knives do I think is better, I would say the Rat 7 because I like the color of the scales better. Based on performance, IMHO, its a dead heat. I am sure you probably already made your purchase but I felt compelled to share my positive experience with OKC customer service. I still love ESSE too, but those prices have me checking if OKC has a comparable knife at a better price point.