I like mine. Marimo moss balls are supposed to be good filters and since they require very little light and are awesome looking in small to medium sized tanks, especially little bowls and Betta tanks, I highly recommend them!
Here (below) is a pic of a little planted bowl I just got started on. The one in the front is marble, "nano" sized, but the giant green glob in the middle of the driftwood is a "broken" one, spread open and plopped over the top. I left it in the bigger fish tank for almost a year, before it collapsed on it self. Then actually forgot about it for awhile, was hoping it would fix itself somehow. Then rediscovered it when I cleaned out the tank! It didn't do anything special but stay alive and pretty green!
So be careful and don't squeeze your giant sized moss ball like it is a sponge! Oh wait that was me!
It was big like a baseball or orange, and it kept getting so much debris on it, I gave it a couple good shakes and that didn't help so I thought maybe if I squeezed it the stuff would come out, but it really broke.
Can't imagine what I was using for brains that day, lol.
Definitely didn't think that through.
When I went to buy a new giant one, I was shocked at the price $20-25, as I paid $7.99 for the original giant one, so I didn't buy another giant one
So I am sharing my warning, "Be Gentle" with them and move them around frequently