Saint's Row. I'm throwing out the graphical differences just because Saint's Row prefers a comedic style. The cars in GTA are beautiful but they're just part of the city. Saint's Row cars all have personality. Most of them can have customizations, the exception being special vehicles. Saint's Row vehicles really take their over the top fun mentality to heart. Even in 4 when you have superpowers that allow you to get around the map faster you still want to drive because the vehicles are so cool. Tron bikes, hover crafts, cyber cars, alien vehicles etc. Also, there's a drift button.