I'm a little dubious as to the notion of "sharpening" knives in the field. How long do you plan to be out? A knife made of modern high quality steel should stay sharp enough for typical outings. Perhaps if you're doing a month long hike of the AT or something you might need to sharpen but you shouldn't need to on a typical hunting trip. I view sharpening as something done at home or in the shop with the proper equipment, good lighting and a solid, steady surface.

In my mind a small ceramic hone is a good implement for doing touch ups in the field. A few licks will bring back the edge most of the time.

The Lansky or Gatco can do a very good job if you're patient, but they have limitations. It's very time consuming and annoying to do longer blades with them since you have to unclamp and move the device frequently.

Small diamond plates such as the DMT DiaSharp line are good for situations where you have to do actual sharpening or repairs (chip removal, reprofiling, etc.). All you need is a spritz of water and you're good to go. Small oil stones are messy and not very effective on modern PM & crucible steels (eg. VG-10, 154CM, S30V, M390, M4, etc.). Water stones work great but are a bit fragile and need to be soaked (generally, not always- Shapton Pro and Shapton GlassStones, for example, just need a splash and are good to go).

I'd rather make sure my knives are sharp at home, done on water stones and/or my Kalamazoo belt grinder, then do light touch ups in the field. Of course, always have more than one knife along- problem solved!