I have two acrylic eclipse, one with fresh water, and one with marine. They are both really small (I have a large glass marine tank too with an eclipse hood) and I haven't had a problem yet with the tank scratching. Even with live rock being put in and out and coming in contact with the sides of the tank. I'm sure they do scratch easy though if you are very rough on them. I like the eclipse filters, so i really do think they are good tanks (in my opinion). I'm sure others have a different opinion on them, but I haven't had problems with mine yet.
