A lot of folks here use a Corona Mill. I nearly bought one but folks here were telling me about the Barley Crusher being so much better so I went that route. It probably doesn't matter based on the efficiency numbers I see in this thread, but a Corona Mill is more of a grinding/milling action which is meant for flours, where as a Barley Crusher uses two opposing rollers to crush the grains and generally comes preset to what you'd use.
I suspect if you do the math you'd recoup your costs on a Barley Crusher in the first few 55# bags, possibly faster on the Corona style even when factoring any efficiency difference you'll see. If I had it all to do over again, I'd still get the Barley Crusher... I'm sure other roller mills are just as good, but I can't speak to that because I've only ever used mine.