Before jumping into this, i was considering all aspect as well all the pro and con of either a glass or a Acrylic tank. Glass tank can be cheaper but it weight much heavier than an acrylic tank thus it can be more dangerous and harder to handle. Since most of the glass tank is jointed together by silicon ,the lifespan of the glass tank is very much depend on the silicon being used as well as the workmanship of the tank maker making the tank .
Although Acrylic tank can be much more expensive , but it is much stronger, lighter and unlike glass there is no "tinted" effect in between the sheet so you will see the "Real" color of the fishes or corals esp clams. However, acrylic tank can be harder to maintain as compare to a glass tank since it tend to get scratches easier but the good thing is the scratches can be repair by either buffering or using special chemical polishing. Whereas for glass, the scratches is more or less permanent beyond repair.