I am also a believer in powered speakers, for versatility and quality as others have mentioned[matched amp to speaker]..I always use a non powered mixer with powered speakers and a powered sub woofer..

You can always adjust your set up for any room..Maybe one powered speaker, or a pair in stereo...add a sub woofer if you need the bottom[dance music]..If you blow a speaker you can rely on the other one to get you through the job, probably without any notable difference..You can use a powered speaker on the floor for good bass response and another in the air for coverage..There are just better applications and backup measures available with powered units..

Second concept..you never can go wrong with quality equipment..It is an investment...invest in quality that will give you a return...My equipment is still serving me twenty years later...and still competes with anything out there..