Feature:
Perfect mix of a sampler and synth. You have full control of sounds and emulation that you would expect from a synth (I'm a Z1 junkie) but you also have sampled sounds layered into the mix. Up to this point, I've been using Z1's for synth and an Emu rack sampler to fill in the gaps, but with the M3 I can now retire the Emu sampler.

Quality:
Quality control is very well done. I noticed the feel of the 88 keys and the responsiveness of the keyboard that has a lighter touch as you get in the higher keys. The keys are nicely responsive to a heavy touch, but what I really like is how responsive they are to a light touch, and even the material used to make the key itself feels different than, for example, my Yamaha Clavinova which has a "slick" feel. The M3 has a tiny bit of "friction" feel that I've never experienced, and what it does is help speed up your dexterity and make scale movements very smooth. You have to play it to understand.

Value:
Compared to other items, I think this is the ultimate bang for the buck, without compromise. Face it, the M3 is a consolidation of the OASYS technology and the next Karma and MOSS Z1 technology. The OASYS is a great keyboard, but the M3 is about half the price with the lion's share of the OASYS technology built into a CPU for quantity manufacturing.

Desirability:
Turn this on in the dark to have the key bender joystick glow along with the color LCD KAOSS panel and the 8 square pads for sound patch effects. It looks fabulous but my reason for choosing Korg is to build upon my experience with a pair of Z1's because I expected some similarity, and that is true. I don't have to learn everything from scratch and feel like I have full synth control of the M3.

Sound:
The M3 has the richest sounds that are perfectly voiced for live performance as well as recording. Korg has done a very good job including sounds that meet the working musician's needs for any music genre. The piano sounds are absolutely stunning. The M3 88 key is a perfect master keyboard to complement my Z1's.

Ease of Use:
This gives you 8 controls that look like a graphic equalizer, but they are actually sliders that control the different sounds and timbres and effects. The Z1 synth had the classic round knobs but the M3 has the 8 sliders that are starting to grow on me.

Support:
I haven't needed support but meet Korg reps at the NAMM shows.

Overall:
I change my master keyboard every 5 to 7 years.