Korg seems to have most support among those synths. Does D-70 have mostly same sounds that U-20 has? I've played U-20 in my school and its sounds didn't convince me at all. They were all (well, almost all) quite dry and cold. They didn't get even close to the warmth and richness that N364 has in all the sound samples and songs i've heard.
If I can't get the N364 (though I found one) and D-70 is my only option, how expandable is it? How good sound cards is there for D-70 and what sound modules (or whatever is their official name) can be attached? I'm quite a beginner in this accessory stuff.
And as I said I found one good-conditioned and only at home used N364 for sale. How much is it worth these days? How much is reasonable price to pay for that?