Circle is great! Less likely to hit a corner and break the plate.

I do think square and rectangular can be very pretty and for some items on the plate it can utilize the space better.

it is all personal preference.

I have round dinner plates, square salad plates, rectangular appetizer/dessert plates. But one of my favorite plates is an oval plate from Henry’s Hunan in San Francisco.

Logic and flexibility = round. But boring.

I have seen square dinner plates, and also paisley-shaped (sort of tear-drop.) The paisly shape is kind of cool to see, but it can’t be easy to wash or store.

For home use -> personal taste.

If you’re running a restaurant -> different answer based on the impression you want to make.

Square. They fit in a more practical manner whether being stored or used. No wasted space.

A lot of plates were traditionally thrown on a ceramic wheel. Hence the circular shape.

Though if you’re working with a ceramic mold, it probably just comes down to preference.

I have several square and rectangular plates that were made using a cheesecloth sling while they are drying and hardening.