I have glass and acrylic, my small 46 gal freshwater tank is glass and it does get scratched every so often. And it changes the color a bit. But it is thinner and doesnt scratch that bad. My 180 saltwater tank is acrylic and it scratches VERY easily. But you can also repair it fairly easily. For outside scratches there are chemicals you can use and for inside ones I heard there was some sort of sand paper like stuff that you could use in your tank with it full of water and then just polish the scratches out. I have not yet done this, but knowing how easy acrylic is to scratch I can easily belive it. One thing with acrylic DO NOT USE AMMONIA BASED CLEANERS. This will cause the acrylic to soften and lead to more scratches. There are a few cleaners out especially designed for acrylic. One I use and if you look can get for fairly cheap is called novus. They make 3 kinds of cleaner, called novus 1, 2, and 3. Works great. Hope this helps