It is pretty easy to make and if you have the right mixture down (with a good internal frame work), you can make some neat pieces. It's super cheap and easy too, so if you have the time to let it soak properly, go for it.

I tried it once to make some base rock for a 150g I was planning on using. Most of it was just flat pieces but I was going to cover it with live rock anyways. I ended up donating it Ace's classroom project a few years back. I wonder if it's still in use there and how it looks today?? **hint hint**