I'm curious myself! I would like to sit down and play both. I can certainly live without the direct buttons, because the X1 and Technics were like that. And of course many of the PA80 fills were so bad I didn't even USE them, so I don't remember how they worked.
The joystick interests me at least as much as the fill button function. Also the physical arrangement of the buttons is important I just have to find a dealer that has all 3: XD1, Vega and SD1.
DonM