The Zo has a heavier bread pan than the 800. The 800’s loaf is a bit dark on the bottom when set for “medium” crust. It turns out as medium at the top and dark, but not burned, on the bottom. The Zo’s two-pound loaf is of “normal” dimensions and fits my bread slicer. The 800 is a wider loaf about 5-1/2″ inches wide.
https://www.amazon.com/Breville-BBM800XL-Custom-Bread-Maker/dp/B004RCNJA0

