In short, both games have their positives and negatives overall - with Forza often putting forward a more 'subdued' presentation while GT7 typically looks brighter with colours that really pop. The overall look of the two games honestly comes down to personal preference in most cases.
However, the outlet does note that car models have the edge in Gran Turismo 7 overall - with PlayStation developer Polyphony Digital modelling its vehicles to the most minute of details. Cars still look very impressive in Forza Motorsport, but GT7 wins out here when you look up close. This helps contribute to DF giving GT7 the nod overall:
"After speaking with the entire DF team and based on the experiences of playing both games, we've decided that Gran Turismo 7 gets the nod as the more visually striking game of the two."
Even with a conclusion that slightly favours Gran Turismo 7, Turn 10 has done fantastic work with the tech behind Forza Motorsport. Digital Foundry was keen to end its comparison with a tip of the hat to both developers:
"Whichever you play, however, there's little doubt that both teams have poured their souls into creating these games. Creating something at this level and this quality is exceptionally difficult - even the smallest error is picked up on by the hardcore. Over the last two weeks, pulling these games apart, my respect and admiration for both Polyphony and Turn 10 has only increased and I cannot wait to see where they go next."