For the most part you really need to know RMS, max excursion (millimeters), frequency range (hertz), and sensitivity (decibels). a lot of people will try to tell you that one brand is the best or another one is the worst but really as long as you stick to well know brands you shouldn't have to worry about getting a quality rip-off. always Research products before you buy them. search multiple sights to get them best deal.