This was my first foray into the world of re-usable menstrual products. I really liked using the sponges, they were soft, easy to get in and pretty easy to get out, and they have all the advantages of tampons, but are natural and reusable. To clean, you just squeezed them and rinsed with water. There's more information on using sponges and how to disinfect them on their website.
The reason I switched from sea sponges to the cup is that the cup can go up to 12 hours, and lasts for 10 years. However, I highly recommend sea sponges to someone who wants to switch from tampons but is nervous about menstrual cups. They are very similar, so it's a painless switch.