My local petland has the strata for 11 dollars for 4lbs, big bag is 21 dollars, so if you have a Petland and wouldn't go there for anything else you might want to see if they have it to try out. So far I like it, its a pain to not stir it up if you muck around in there but it settles quickly and fish and shrimp seem to like it.
Moss could easily grow on it, its just foam. Throw a few pins in it for support, and moss it up. These thanks are awesome, so pumped i got one.
I don't think moss will grow on it, it needs to hold onto something and it'd just slip off the styrofoam. I tested it out, the best I could do is put up some mesh with pins but I didn't like the look of it so I took it down.