Cons:
1- I find the weakest sounds are the saxes and you really have to get in there and tweak them adding EQ/FX to get the sound you require eg: Growl sax.
2- The key feel between the Pa900/S950 is pretty much comparable.
3- Although Korg offers more then enough style varieties I don’t use that many styles besides my custom edited “Easy 30+” which I can cover just about any genre of music unlike many players who don't gig or have ever been in front of hundreds of people on stage we use the arranger KB to back up our singing first. To me Korg is geared Toward the Pro Player.
4- On some Drum sets tweaking has to be done to get the right timber, resonance to the snares, bass drum, cymbals, etc,..
but easily done in Drum edit mode.
5- Many organs have a velocity pressure triggered Rotary effect which I can live with but don’t particularly like vs. some that have the joy stick to manually activate the Leslie. Otherwise great Organ sounds love the Gospel Organ.

I know as I go along I'll have more Pros/Cons to share, today I'll play it again at a 2hr luncheon/dance job, more to come.. I have owned so many KORG Models including the KORG SaS-20, i3, i30, Pa60, Pa80, Pa500, Pa800, Pa3x,... But I will say this,.........
There are So Many Great features packed into this KORG PA900 Arranger keyboard that certainly Outweigh the negative in so many ways.