Hi John --
Aside from the sax sound on Yamaha, what really sold me is the SA/SA2 playability and responsiveness, for lack of other terms. Yamaha really nails this. I can play a sax line by intuition and the instrument seems to be an extension of my gestures.
Can Korg do this? I &^^%$&^ well don't know. Korg arrangers are completely MIA (missing in action) in USA retail stores. I'm not about to order a $4K arranger on-line just to try it and send it back! Someone praised the Kronos acoustic instrument emulations, but they left me cold.
It's a musical instrument, so honestly, I don't know what to expect unless I actually play it and hear it in person.
Good points -- pj
Well, I haven't tried the PA5x yet, but my experience with the PA4x/PA1000:
The ariculations aren't as intuitive, no. For example, the body tap of a Classical guitar on Yamaha is controller by a pedal; on the Korg it was slapping the joystick down (-y), which meant I couldn't play the guitar sound with both hands, and often meant that you'd accidentally pitch while slapping the joystick. Even more baffling, the Yamaha body tap works tapping the pedal regardless, but slapping down on the joystick *only* produced the body tap sound while you were holding at least a note. Which often meant the tap wouldn't sound if it'd already instinctively lifted my right hand off the keys.
Yamaha S.Art2 saxes glide (glissando) very naturally and effortlessly, automatically going monophonic/polyphonic as the transitions require. The Korg S.Art2 sax is always poly, meaning when you hit the glissando button, you have to time letting go of the note *just right* or you'll break the illusion (and you'll hear 2 saxes momentarily).
On the other hand, their megavoice noises (fret noise, pick noise) are basically a function of S.Art (DNC on Korg) rather than megavoice; so you can play all the guitar sounds from a style without learning *how* to control them.
Personally, I found the strings & brass on the Pa4x too synthetic, which is why I always used Yamaha in my orchestral demos (and, registrations are a necessity to me). However, the behavior of their Tutti is *much* smoother than Yamaha's (it reserves more than 1 polyphony for the cymbal crash)
EDIT: forgot to mention, their automatic quantizing for chord changes is better on Korg. On Yamaha, it's possible to change chords *while* a note is playing, and you'll hear a funny correction; Korg seems to quantize your chord changes in real time. So that's nice.
Conversely, I found it much more difficult to program styles on Korg (and indeed, even to 'load' them into a fixed array slot), but that could just take getting used to the workflow.
Mark