Ferry to Matsu, then to China

I understand there’s a ferry from Keelung Harbor to Matsu, then you can take another ferry to China (assuming you have the visas/paperwork for it).

Has anyone here done this? What are your experiences? Are reservations needed, or can you just show up at the ferry terminal and buy a ticket then and there?

If you want to skip Matsu then check the List of Ferry to/from Taiwan