IMO..... Gun-Kote is the best I've found. I've tried ceracoat, etc. But for cost, easy of application/use, and durability, I feel Gun-Kote wins hands down. I tested it by building myself a smaller chef's style knife from my "Fossil Damascus", coated it with satin clear.....and after 11 years in our kitchen, the blade looks like it did the day I finished the knife. NOW, that being said, it requires some practice and special technique to apply, so that it will stay with abuse, and not look like a plastic coating. What I do is use it on blade at are at the very least etched (damascus, or plain steel). It's recommended to sandblast prior to application, but then you're stuck with a "sand blasted finish" look.
I clean the finished blade with acetone, then windex..... and I use a cheap Harbor Freight air brush to apply the straight produce (no thinning) in VERY LIGHT passes. (Gun-Kote IS NOT one of those thing where more is better!) It's hard to explain, other then to say if you see it on the blade... like wet spray paint, you've gotten far too much of it on the blade, and it WILL come out of the oven looking like it's been laminated in plastic. When applied very lightly, and baked at the correct temp, for the correct duration, it's almost unnoticeable, and darn tough stuff!
This is a "BBQ/Kitchen Utility" knife of twisted "Fossil Damascus" that I made for one of our friends at Church about 5 years ago He says he uses it almost daily......I've seen the knife recently, and beside a bit of fading on the Blackwood handle, it looks the same as in this pic....
On the other side of the coin, if you don't want to Gun-Kote a blade, my vote is wax, specifically I prefer Mother's Caranuba Cleaner Wax. I've tried all the high end waxes, including RenWax, but simply don't like them. If it has a "loud" smell of chemicals.....steer clear. Of course it's a repetitive method, but far less often then using an oil would be.