Besides being unclear whether one is better or worse, it's not clear there's even a practical difference when a significant number of programmers will be navigating and learning code through an IDE anyway. They'll be jumping from function to function, barely even aware of which file each one is in.
Personally I prefer smaller files, but that's only because of compile times. I started my career with punch cards, so I know what slow compile times look like. For a long time they seemed to be getting ever shorter, until I switched to a "modern C++" project. Now compile times are not quite back to the punch-card days, but back to maybe late 90s, and breaking stuff up into smaller files helps.
