I have a Corona grain mill. It's very heavy duty and will grind hard wheat, malted barley, or coffee with ease. I would recommend it, however, I don't have any experience with any other brands.
I have 2 Coronas. There are a lot better products out there. Walton Feed has a good comparison that will help. Country living is about the best but is expensive.
I'd recommend the Family grain mill. Extremely well made, lots a flexibility as far as attachments and very easy to clean.
When thinking about getting a grain mill I go first for convenience (electric) coupled with a solid contingency (hand crank). The beauty of this product is it's modular. I have both the bosch built motor as well as the hand crank base as well as several attachments
Expect to pay a few bucks for a high quality mill. I think when all was said and done I paid over $200 for it.