To me the main advantage of the powered speakers was the built-in bi-amping. I had JBL Eons, and as the others do, they had seperate amps for the highs and lows. Very efficient and light weight.
I began playing in some situations where monitering was very important, and rather than purchase powered monitors, I went back to using unpowered speakers and merely plugging unpowered Hot Spot monitors into the back of the mains.
I think the powered speakers sound better overall, unless you do bi-amp the unpowered ones. This calls for an extra power amp if you want to run stereo. I always run stereo, mostly for my own enjoyment!