I was in the Apple store today and tried both side by side. Whether it was photos, videos, Safari, Youtube or the home screen, everything looked equally good on both. Only HDR videos were a little better on the 12.9. But it was also almost imperceptible. In no way is it a wow effect in any form. Of course, it could also have something to do with the fact that the light is very bright in the stores.
Are you just imagining that the 12.9 has a better screen?
It certainly doesn't, at least in bright conditions.
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