Slow. Does not function correctly all the time. Changes settings on its own for both your account & shipping. Seems as if Mercari is trying to push their failed local delivery. Also when shipping costs increase (which is frequently), you must go back and adjust every item, it will not adjust automatically as indicated. Additionally, they no longer seem to honor the shipping insurance with their prepaid labels. & with new tax laws, this seems to be the most hostile environment to sell your unwant