I don't own this oven, but in general people prefer to have fire on the side, if the oven allows, to monitor the baking process. With fire on the side, you can see how quickly the crust is taking color, and rotate the pizza just at the right moment to avoid over-charring. With fire on the back, you can't see what's happening to the crust, and need to rotate just to see where it is.
I used to have a big WFO, now using a tiny Bertello. The biggest problem for me, is that with the fire in the back due to the Bertello size and construction, I cannot monitor the crust progress. Especially for Neapolitan pizza, with very short baking times, that is a problem
Heat distribution and convection in your oven can change the above consideration. Also how big of a pizza you can bake depending on the fire position (not an issue with a traditional dome oven, can make a difference with a barrel-shaped oven)