I can't directly answer your question, but perhaps I still have something useful to say?
I recently bought a BK-2, and decided not to get a BK-22. Instead, I got the older model with the FRN sheath, and also bought a Spec Ops sheath. Most of the time the knife lives in the Spec Ops, which I am Very happy with. There are times, however, when I know that I will spend much of the night in and out of waist deep water. Here, the FRN sheath shines - water rolls right off of it, so my clothes dry out quickly near where I carry it, and I don't have to worry about throwing a soggy knife sheath in a pack with my other gear. Best of all, rinsing muck off of the FRN sheath is as simple and shaking it back and forth in the water (I ripped off the FRN sheath's webbing dangler).
That said, if I had to choose just one sheath, I'd get the BK-22. The new sheath is very similar to the Spec Ops one. It has a storage pouch, which is great for keeping a pocket sharpener and a back up compass, it doesn't dangle horizontally as soon as you unbuckle the retention strap around the handle, and it doesn't kill your thumb every time you try to draw the knife like the FRN sheath does.