Warning--anecdote ahead:
The two batches I brewed with a borrowed corona mill had a noticeable grainy/straw flavor. Of course it could have been something else but I haven't had that experience with my roller mill.
Caveat-the corona may have been poorly adjusted or I ran it too fast. I prefer a roller mill because it has only 1 adjustment and requires very little fiddling to get consistent results.
I have been using my Corona style mill for 6 3/4 years and I get very consistent results. When the results are less consistent it in not because of the mill.
Cereal killer here. Set it to credit card gap, and I get 82% efficiency almost every brew. Sure, it grinds a bit fine at that setting, but for BIAB, its no big deal. Not too fine though.
I wouldn't even mess with a corona style. Save up for the Cereal killer, and get a corded drill. You CAN hand crank, but... $40 buys a nice "Skil" hand drill at lowes, I even paid the extra $5 2 year warranty, just in case
Why all the hate for the Corona mill. They are a bit of a PITA but they work very well. That said I want a good roller mill, but because I think it will be easier to use, not for the grind. I will have to see sometime in the future if it makes my beer any better. I think if it does, the change will be minor.