It might not look that different in the pictures but there is significant difference between the results. Shoe applied with Collonil Diamant does feel much more moist, very so slightly oily, and with deep luster that I've failed to capture. Shoe applied with Saphir Renovateur appears to be shiny, polished, conditioned but yet slightly dry. It's probably like facial care products; there are thicker creams that conditions better and there are thin and waterly creams that slightly conditions but does not leave a greasy touch.
I still have one and half cans of Renovatuer but I am now a convert to Collonil Diamant for conditioner. But I am still sticking to Saphir M'dor for shoe creams.
You might be subjective... why don't you ask a 3rd party that does not know the details to give you their opinion on the shoes?
Then you might call it a Design of Experiments.