Also, line-in is a less noisy input that mic-in, and enables you to handle louder sources than mic-in. For the average loud rock type show, line-in is the way to go if you're using mics with a battery box. For quieter shows, you might need mic-in if you can't get the gain you need when going line-in. Getting a preamp (like the Church 9100) will enable you to get clean gain so that you can use line-in even for quieter shows.