Milling flour. Stone milling is said to be better as it does not heat up the grain and damage nutrients, however these WonderMill Whisper Mills from ebay (about $100 to $125), move a lot of air through so the flour temperature is only about 100 degrees F on exit. The amount that a stone mill heats up the grain depends on ambient temperature and how much grain is milled as well as the size of mill stone. Meadows and New American are popular stone mills. We are looking at some 20 inch Meadows stone mills that are 80 to 100 years old that would need some work including "dressing the stones". A used WonderMill has the capacity of an 8 inch stone mill costing $2000, although the WonderMill is not really designed for continuous use. https://meadowsmills.com/StoneBurr I think the final flour product can be similar. A lot of it is in the sifting - whichever type mill is used.