What you get, above all else, with high efficiency single driver systems is explosive dynamics, a vivid and lively sound that engages the listener. But, that often comes with the tradeoff of frequency response peaks, un-natural tonal quality of instruments, bass deficiency and a "rough" sound. Similar problems are common to horn-based systems as well. I like the sound of these types of high efficiency systems enough to live with these trade-offs (I have a horn-based system). The trick is to find designs that minimize the trade-off while still being able to deliver the goods. What represents the best balance of trade-offs is a matter of taste. To me, the Charney speakers are shockingly good because they do a great job of minimizing problems while still delivering the excitement.
The Cube Audio speakers deliver the dynamics and are reasonably devoid of some of the extreme peaks I've heard with other full-range systems, but, they are not at all close to the Charney speakers in terms of tonal balance, smoothness, and suitability for all types of music. They are also more efficient than the Cube Audio speakers, making them more suitable for use with very low-powered amps (my favorite kind).
I think anyone in the market for these types of speakers should hear both and make their own decision; certainly, they are both contenders.
