Pro audio mixers are different from DJ mixers because they are designed to mix multiple microphones as opposed to line and phono level sources like CD and vinyl turntables. Most Pro audio mixers have features like individual channel equalization and auxiliary and effect sends. Some of them also have sub groups that allow you to assign channels to groups for easily making adjustments to entire groups of mics (like a drum kit). The first question you should as is how many channels will you need. You may also want to have effects built in.