Koda is a knob. Karu is a fire.
The Karu 2 is Ooni’s current 12-inch multi-fuel oven: wood or charcoal out of the box, an optional gas burner if you get tired of feeding it, a real flue, a glass-ish door, legs that stand on a table. It is how you get smoke without buying a Dome.
It is also slower to live with than a Koda. You light it. You wait. You learn the fuel. Buy this when the point is wood. Buy a Koda when the point is Tuesday. Check Amazon for the current burner bundle — it is often sold apart.
Buying guide: Best pizza oven for a home kitchen, Best gas pizza oven for beginners, Best wood fired pizza oven, Best indoor pizza oven, Pizza oven temperature, How to clean a pizza stone, steel, and pizza oven