I don't think the DSI sound and the Japanese analog sound are really comparable, or take each other's place....I think the prologue sounds awesome...really. I think it would make a great contrast to the American sounding P6/OB6. You have a few flavors of that sound, but only Korg has really delivered in the analog world for new stuff from the big 3 Japanese companies.
But seriously, you're getting bitimbral 16 voice discrete vcos with what sounds like an awesome filter with a 3rd digital oscillator that can do fm/wavetables, awesome effects and analog comp...man, not a lot to dislike....it IS a good deal on the Prologue, and it looks to be very well built. People want to put a VS. between DSI and Korg...I think they would compliment each other nicely!
Just like I think classic Roland anapolys compliment the American sounding Sequential and Oberheim sounds, I think this Korg would compliment them as well.