Single driver speakers. Are they worth considering ?

I don't mean electrostatic. How close to a full range speaker can you come with single driver ?
For a very reasonable cost the Omega speakers (Especially those utilizing the Alnico magnet)  consistently received high praise for their natural sound quality.

Moving to a higher price point the Cube Audio Nenuphar has  been bestowed with excellent reviews by professional writers and outstanding owner feedback testimony. It could quite possibly be the pinnacle of upper tier single driver speakers,. Purity and convincing realism are repeatedly cited.
I recently rebuilt a pair of Ohm Walsh F single driver, no crossover-full range speakers. Favorite speaker by far out of the many I have listened to though I don't have much experience with super high end stuff. Seems like one would classify it as full-range as it is a single cone with single magnet. Plays frighteningly low with crystalline highs (or whatever descriptive crap you want to use). Soundstage is deeper and revealing to the point where it seems almost like a disney illusion. 
Of course only sounds really good when 6 feet into the room so can only listen when my wife is gone (which isn't much these days).
For fun I bought a pair of Audio Nirvana Classic 8 Neodynium drivers and built the recommended enclosure for them. A pretty simple project that yielded results that were much better than I expected. I listen to them quite often when I'm working in my shop and power them with a pair of Pass ACA amps that I built. I was once a single driver skeptic, but not any more.
Great thread.  I'm looking forward to hearing about more user experiences with different brands/approaches.
Evolution and progression does occur.  Someone's experience with a Lowther single driver speaker has little to do with hearing a Nenuphar or Charney. Faulty extrapolation.