
Build Quality
I was nervous after reading the many forum threads about quality issues, but am happy to report I have no problems in this area. It seems well made and, while not exactly built like a tank, solid enough to get the job done.
The end caps are certainly the least attractive part of the instrument (and not exactly a tidy job with the glue where they join the main body!) but I have no concerns about their strength or longevity.
I can’t hear the fan at all.
It took me a while to get used to the key action, but after much playing it has grown on me. The only thing I still don’t like is the amount of key noise when I play organ glissandos, but that’s easily drowned out by cranking up the volume!
Things improved dramatically when I adjusted the global velocity and aftertouch curves (in opposite directions, making it easier to get low velocities and high aftertouch values). I know this is a very subjective, personal thing, but the default values just don’t seem right for a synth action keybed (to the point where it was almost impossible to press hard enough to get aftertouch values above 60 or so). I wonder how much variability there is between boards, or if the defaults are just set wrong? I bet a lot more people would enjoy the 61 action if it was set up the way I have it now rather than how it came out of the box.
The ribbon controller is ok, but not as responsive as the touch pad on my aging Z1 (still unrivaled for fine detail vibrato and wah, if you configure it so sensitive that you can just rest your finger in the center and then rock it from side to side without having to slide at all). I love the two Kronos joysticks, though. They work nicely together and provide a ton of fun for responsive realtime sound mangling.
Pianos
I don’t have much to say about SGX1 and EP1. They sound fantastic, are great to play, and easily tweakable to match personal taste or make them fit in a mix.
I’m in the minority in that I prefer to play these sounds from an unweighted keyboard (I started out as a synthesist, then gradually worked my way backward to piano sounds, so I’m just more used to that action) but I have to say to those who argue you can’t properly enjoy a piano from a synth keyboard, that’s a load of baloney! In fact my biggest complaint about these sounds is that whenever I settle down to work on a track, I seem to get stuck jamming with the German Grand or a nice overdriven Rhodes, then realize it is six hours later, time for bed, and I got no productive work done at all

Organs
I’m digging the CX3 engine, but not so much the presets. There are too many safe, middle of the road sounds, all basically the same thing just with different drawbar positions, and not enough that push the limits of what this engine can do. It gets much more interesting when you start tweaking, though. I think Korg would benefit from looking at the presets from something like NI B4, which (especially for someone like me who loves the sound but has never played a real Hammond) do a better job of demonstrating the wide range of timbres that can be obtained.
Wave Sequencing
This was one of my biggest reasons for getting the Kronos – I’ve always wanted a Wavestation but for some reason never got it together to purchase one. Kronos really can make all the same sounds, but with vastly improved effects, filters, and realtime control. Pure awesomeness.
My biggest issue with these sounds is that, fun though they are, they’re just so dang distinctive that the presets are basically useless (same issue as the original Wavestation, with so many instantly recognizable patches that ended up in oh so many TV scores). For any serious use, I will have to program my own wave sequences, an area I have only started to learn about.
But the truly amazing thing, which I’m surprised I have not heard more excitement about, is that this Wavestation is also a sampler! How cool is that? I can record my own audio fragments, then rearrange them, sequence them, make them groove, and wrap the whole thing up into one of those awesome evolving rhythmic pads or soundscapes. I’m really excited about this.
Acoustic Emulations
I love the basses and drums.
Strings are ok, especially some of the smaller sections. Surprisingly, the big lush stereo strings are improved if I layer them with my ancient Roland JV1080 orchestral expansion card! Somehow that combination manages to be richer and more realistic than either alone.
I agree with the general opinion that the sampled guitars are disappointing, but I’m a guitarist and so had no interest in these sounds to start with. I’m also underwhelmed by the various ethnic instruments.
I like the brass and woodwinds more than I was expecting to, especially those from the EXs3 library. I think Korg did themselves a disservice with the preset ordering here, as someone auditioning a Kronos for the first time will find the lower quality EXs1 winds before discovering these better versions.
Unnecessary HD1 Sounds
I don’t understand why there are so many piano, organ, FM, and analog synth sounds in HD1. These are less responsive than the dedicated EXi versions, and I cannot imagine myself ever using them.
Synth Engines
MS20 was the big surprise for me. I love this thing! It’s not a particularly general purpose synth (not something I would pull out when trying to recreate a specific sound), but it just oozes personality, with random knob twists veering the sound off in all sorts of fascinatingly nonlinear directions. For me it strikes the perfect balance between crazy, aggressive, distorted, unpredictable, yet tamable just enough to be musically inspiring.
PolySix bores me. It sounds fine, but I haven’t (yet?) heard anything from it that particularly got my juices flowing, or that I didn’t feel I could have equally easily created elsewhere.
I haven’t yet spent enough time with Mod7 or AL1 to properly evaluate them. I have a feeling I’m going to be using Mod7 a lot, but the learning curve is pretty steep.
STR1 is, in my book, winner #2 after the MS20. I love all the weird kinda-acoustic-but-not-really noises it can make. And the acoustic bass patch is just fantastic, expressive and weighty and woody and responsive in all the right ways.
The STR1 nylon guitar doesn’t convince me as an actual guitar, but is seriously useful as an element to layer with synth voices. Before I got the Kronos, I would often layer synth leads, pads, comps, etc, with a marimba, vibraphone, or gamelan sample from my JV1080, mixed around 1/3 the level of the main synth. This adds a nice percussive element to the attack, and the sampled layer makes otherwise synthesized patches more organic in a way I find musically useful. Well, the STR1 nylon guitar is PERFECT for this kind of layering. It’s incredibly responsive to playing velocity, and a ton of dynamic variation can be achieved by using the vector joystick to morph between harmonics or that softer more bowed attack. Many of my favorite old Z1 patches are given new life by this layering.
Other Stuff
I haven’t used the sampler or sequencer at all yet. If only the basic sounds weren’t so much fun to play, maybe I’d have more time to explore these other areas!
For some reason I haven’t clicked with Karma. The idea intrigues me, but I find myself liking it less in practice than I do in theory. Maybe I need to give it more time, or maybe it’s just not for me (I don’t use arpeggiators that much either).
I agree with the issue raised elsewhere that the drum track volume is consistently too high. I’m playing away, with a patch turned up nice and loud, decide I want some drums, and YIKES! Quick reach for the volume knob to avoid waking the wife

Oh yeah, in case you haven't noticed yet, I love this thing. It sounds great, is versatile, fun to play, and most importantly, I find it musically inspiring. And that's what counts at the end of the day, right?