The first question would be, are you going to use a Leslie? If so, stick with the Hammond XK1 or XK3. They will provide the best raw organ tone to use thru a Leslie. If not, I would still consider the XK1 because I've heard some great things about it, with the improved Leslie simulator, chorus/vibrato, etc. If it's physical features you're looking for, you may like the XK3. I personally am not too crazy about the XK3's Leslie simulator. I use it on occasion in my own practice time when it's late at night or something. But the physical features really make up for that. You get 12 inverse preset keys, 3 sets of drawbars; upper, lower, and pedal. Vintage style C/V rotary knob, and it can easily be expanded by adding the XLK-3 lower manual board with the stand as well. Hope this helps ya out.