I’ve found that newer folks tend to prefer keys with fewer accidental: C, G, F, D and Bb
Whereas there is a tendency for more experienced players to prefer keys with many flats: Db, Ab, and so on…
And (appropriately for the submissions topic), I think lot of this preference comes down to the fact that we tend to learn keys like C first, because the notation is simpler and it’s easier to remember the spacing. However most of the pianists I’ve talked to who prefer the flat keys will prefer them because of “how they fit under the hand”.