i'd say my shop listings are half/half.
my home is extremely tiny, which swayed the opinion for made-to-order only, but i discovered vacuum storage, and also love to be able to ship items immediately and make one-off pieces that will never be recreated.
i love making designs with the customers having the option of customization, but some of my things i want to see as one-of-a-kind.
with school/dayjob coming soon, my one-of-a-kinds or ready to ships will be a lifesaver and stressbuster for me.