We've had the ZU Druids for about 3 years. They handle anything we throw at them (and that is quite a wide range of music). With our smallest amplifier we can play the Druid to any level we want.
Our amps also work well with the Coincidents, but our S-30 (our smallest amplifier) is not enough power IMO for the Coincidents, although it sounds fine on them. I think the volume level is a matter of taste in this regard and a lot depends on the listening room. I'm often accused of playing things too loud :)
So the difference is efficiency and the Druid has slightly more bass (but overall that is probably not going to mean a whole lot). Otherwise with our amps the two speakers sound very similar.
Our amps also work well with the Coincidents, but our S-30 (our smallest amplifier) is not enough power IMO for the Coincidents, although it sounds fine on them. I think the volume level is a matter of taste in this regard and a lot depends on the listening room. I'm often accused of playing things too loud :)
So the difference is efficiency and the Druid has slightly more bass (but overall that is probably not going to mean a whole lot). Otherwise with our amps the two speakers sound very similar.