The KK has two strong points IMHO, while it's limitations seem more or less secondary to me - after taping the name
1. Sound
The interesting thing about this synth is it's VA quality, with the various filter models sounding really interesting, as far as the demos tell. AL-1 has a much more advanced synth structure, but it has a very neutral basic sound and less audible filter differences, which makes it hard to get such a varying sound spectrum from it. And all the essentials for sound programming seem to be there in the KK as well. For example, to me it is ten times more important to have Oscillator sync on board (expressive live play), than to have a third or fourth envelope available (nobody will notice that consciously in loud live band context).
From the demos I get the impression of a VA which offers definitely a more interesting basic sound plus more different sound colours than a Radias - whatever the Radias may have in advance in other areas. And having basic effects (plus a bit more, with ringmodulator, bitcrusher etc.) and the tube available on board as well, means that you can do a lot with this one 7kg thing on a second tier, instead of carrying unnecessary secondary stuff (tube preamps, hardware effects etc.) around.
2. Live usability
The KK has what is completely missing on the JP80: a controller field worth using, and allowing to shape sounds on the fly like it is required for analog synth structures. You get fast (re)programming in immediate reach (great haptics: very nice knob size). This just fits like a shoe, comparable to classic analog synth surfaces (not to big modular systems or polysynth dinosaurs of course) - even if I don't like to have cutoff and other often used knobs to the right. Al in all, Korg seems to offer a "bread and butter" synth with low aliasing and no audible midi stpping while moving controllers: you probably can play synth solos in good quality, do easy 2-splits, get pads for backing, or play a juicy synth-bass whenever needed. Definitely looks like fun in band context!
This (in sharp contrast to the JP80) is what I would call a performance synth! If it survives the first practical tests, it might become an ideal second tier synth companion for a weighted Kronos, allowing you to use it's synth sounds and also play Kronos VA sounds from there: would be a great double pack, if the KK works as well as it seems.
The "manual" is nothing but a short introduction. It doesn't tell much about the synth structure. Let's hope for the parameter guide to appear soon.
Doesn't the stuff from 2:10 on sound nice?
http://www.youtube.com/watch?v=4RFr1dKpx24