I found the NutriMill to be a bit slower than the WhisperMill and not quite as amenable to larger beans, but not only does it make a very fine flour, it does a great job of coarser milling, which the WonderMill cannot do (like cornmeal or coarse wheat for cereals, etc.) and it does have a much greater capacity (20 cups flour vs. 12 cups flour). Flour quality is excellent in the NutriMill.
This mill is a little quieter than the WonderMill, but it does run a bit longer, so that is sort of a trade-off (some people consider it just a different pitch). The mill can be turned off and on with grain in the hopper, which is a no-no with the WonderMill. If you are interested in the convenience of a hand-operated mill for non-electric use, the company hopes to introduce a hand-crank attachment for this machine in the near future. Limited lifetime warranty.
I have used a WhisperMill (now manufactured as the WonderMill) for six years and love it. It quickly makes a very fine flour for me with all the different grains and beans. It is very convenient to operate and is self-cleaning except for an occasional rinsing of the flour canister/separator cup.
Although it doesn't have a large "footprint" on my countertop because I stack the flour canister atop the unit, I do need to have space for the canister next to the unit when I actually run it. The hopper holds 8 cups of grain at a time and mills it in minutes to approximately 12 cups of flour. Limited lifetime warranty.
Also available: Wonder Junior - handcrank mill. Price for Junior: $220 deluxe (1 set stones, 1 set stainless steel burrs, plus clamp; improved auger yields 1.5 cups in 1 minute); $175 basic (1 set stones, no clamp)
UPDATE: I purchased the Wonder Junior Deluxe and was impressed with the solid build and straightforward design. Worked great! Since I'm not very strong, I prefer to run the grain through once on an easy setting, then run it through again to get the fineness I want. It doesn't take much longer to run it twice on a don't-hurt-myself setting than it would to run it once using muscle I don't have. Not my first choice for doing 8 cups of grain at a time, but be quite workable if I had no electricity.
Click here to learn more about improvements made to the newer WonderMill (vs the older WhisperMill).
We now offer KoMo (Wolfgang) electric stone mills. Details coming soon!