I ordered a King Song 14B w/ a spare 148 watt-hour battery. My de facto car is a Ninebot One C+, and the KS14B offers a similar riding experience. I would rate the Ninebot as the better cruiser, while the KS is a bit better with tight turns and curbs. But the similarities are far greater than the differences in daily use.
I bought the 14B specifically for air travel, and I was not disappointed. I discussed the finer points of the lithium-ion battery with the airline in question, and confirmed that a 148 watt-hour battery bundled in my carry-on bag would be allowed. The relatively tidy dimensions and weight of the 14B sans battery fit made packing and lugging my suitcase an easy task. It is very satisfying to have an electric unicycle at your disposal when you step off of a plane in a remote community.
The range with the travel edition battery is modest, I have averaged 8 km per charge so far, but it actually feels like a Goldilocks moment: enough range to forego walking, taxis or car rentals, but in a package light and small enough to justify taking it with you. The swappable battery is a great feature. There is no such thing as too much range, but the penalty is paid in cost, weight, bulk, and charge time.
If I were a first-time buyer, I would rate the quick-change battery feature as very important. To my present knowledge, that puts the King Song in a field of its own. Not brand-specific, but in my view, owning an electric unicycle will make you a better person of sorts by forcing you to deal with people. You will find yourself talking to strangers at length about exactly what you and that thing at your feet are doing. I have been often chased by children who inevitably want to try it for themselves. If we had these things in the Middle Ages, the Pied Piper could have managed without taking any music lessons.