I want to upgrade my sharpening stones and was thinking about one of the diamond stones available. My old Arkansas stones are no longer flat and quite oil soaked from years of use.
I'm a big fan of Buck and they have some diamond stones on their site.
Do they really saharpen any better than an Arkansas? What good and bad is there to know?

I wont say anything bad about the diamond stone they are great! If your stone is wore out get a new one. Dont limit yourself to one setup. I dont understand the oil soaked part. I only use oil to float metal flake out of my stone. I also think I have used carberator cleaner to clean my stone. I dont use oil to sharpen (or hone).