I have a corona mill. It's fine for crushing steeping grains and even for a few pounds of grain for a partial mash, but it's way too inconsistent for all grain batches. I'm getting a Barleycrusher very soon.
__________________ Knucklehead Brewery, Est. 2007
Always do sober what you do drunk. That will teach you to keep your mouth shut. -Ernest Hemingway
save and get either Barley Crusher or Monster mill no question
Spoken like someone that has never seriously tried a Corona, I am guessing???
Corona mills (and the knock-offs) work fine. They are temperamental to get adjusted, but once you figure them out they do a good job. There are even a number of us here that get 80%+ efficiency with them.
I had a Corona mill for several years. It was difficult to adjust, and slow, but it worked. I couldn't get as consistent a crush as I do with my roller mill (JSP) which would have made it more difficult to get consistent efficiency, but in those days I didn't know or worry about efficiency.
If it were going to cost me $60 to get a Corona, I probably would save my pennies and buy a BC (which you can get shipped for just about twice that).
But, you shouldn't have to spend THAT much for a Corona; keep an eye on eBay, and I know lots of people have upgraded, so I bet there's quite a few collecting dust on a shelf somewhere.