I love mine. (My apologies for the length of this)
That being said, if you don't use diamond (dmt) stones, or SiC sand paper you will have a hard time sharpening it. I use the dmt diafold in fine/e-fine and it works well. Though I only use the fine side. I am sure their medium would work nicely as well considering the large carbide nature of non cpm d2. Just keep in mind that with the carbide structure of d2, it will like a toothy edge and hold its working edge for awhile even though the initial edge will (seemingly) lose its freshly sharpened bite.
I have just received a ceramic rod that I want to give a go, I noticed it seems to polish my 01 and 1095 blades more than I prefer on my d2. I will update my findings. That way, if you have access to a ceramic rod/stone, you won't have to try it yourself, lol.