Single driver speakers. Are they worth considering ?

I'd rather pass a gallstone HA. Actually I have single-driver speakers, of course it's all in the application as anything else. Plus we choose our compromises.

Once you listen to a single driver speaker, you will never go back to a multi-driver speaker that is nothing more than a symphony of disjointed monstrosity :-)

Those Charney Audio speakers look great and have some excellent reviews.  It looks like the company is not too far from me in NJ.

Another single driver variation is the Voigt Tube like what was featured in this Tech Ingredients video:

https://www.youtube.com/watch?v=EEh01PX-q9I

On single drivers the  frequency response tilts steeply upwards from bass to treble there's Beaming at high frequencies,  top end marred with ripples and IMD is a problem and they aren't full range. Other than that they should be fine. 

Look at active  3 way with DSP controlled crossovers.