I've been using the QSC HPR line of powered speakers for about 5 years now and have no complaints. As someone who provides small to medium-sized sound systems for DJ and live events, these speakers fit my needs and offer a great bang-to-buck for what I do. I recall paying around $700-900 a piece for them (new), so not the cheapest or best in the world but still a decent speaker for under 1K/ea and I personally think they sounded the best among the other speakers I listened to in that price and performance range.
Why did I choose powered over non-powered? Mostly for cost, convenience, and physical appearance. A lot of the jobs I do are at the wedding or corporate level, and an amp rack was just one less thing I had to worry about hiding. I also don't have to worry about buying expensive amps, amp racks, and cables needed to support non-powered speakers. Granted I usually have a FOH rack anyways, it's nice not to have to NEED anything else to make the speaker work. Would I do a large, 20+ speaker array with these - no - and they're not designed for that. Sure, there are plenty of powered speakers on the market that are a significant step above what I use, but for what I do their cost/convenience/performance ratio just made sense (and given QSC's success with powered speakers, I'd say I'm not alone). Hope this helps!