I have them, and had them up in my 55 when I had it running before. First..as to Slips comment..yep they are plastic. I thought they were neat, and I did have gravel on them,a nd when I did the plastic plant and plastic rock thing they looked just fine. I have since decided to go the realistic route and don't like to mix the real with the plastic.
I have ditched all my plastic plants and some of the cheesier rocks, but I did keep these, and the interlocking rocks, by the same maker I believe.
The problem, IMO..is cleaning under and on top of them. I use a python and it knocks stuff around and out of line, so you have to straighten out everything afterwards. And you can pile too much gravel on them so they slip out of line...terraces look rather funny when crooked. I put some shorter plants on top of them. I had tons of plants..
I did like them..and may use them again..or maybe not. Haven't decided. The fish like them...somewhere to hide under. I'll see if I have any pics of my tank when I had them.
They aren't really cheap tho... :laugh: