For regular loading, on-press is faster and works fine.
For precision loading - it`s the only way to feel the primer seat properly. First the anvil touches, then the anvil is partially pushed into the primer cup and you`re done. Can`t feel this with on-press priming.
Unless you are in the habit of "mashing" the primers, this is as far as you will go with on-press priming too. So?