You will have a more clear view of your fish. If you are wanting to modify your tank for a sump system or canister filter drilling into an acrylic tank is pretty easy without worry of cracking or breaking your tank. These tanks are also very difficult to pull apart and in large tanks they are less likely to break apart and leak over time than glass.

So the downside to glass aquariums is that they are heavier are difficult to modify and can chip or crack more easily. If you are trying to modify your glass tank drilling into it could accidentally crack or break the panel and then you would have to replace the panel or maybe even the whole tank. When viewing your fish they may appear distorted and the type of glass can cause a green tint to everything so if you have brightly colored fish a glass tank might make your fish look less vibrant.

Glass tanks also do not have great insulation so you might have a larger electric bill trying to maintain your tank temperatures with a heater or chiller. Acrylic tanks have their downsides too, they tend to be more expensive than glass, and they are easily scratched when aqua scarping or decorating your tank. Many types of acrylic tanks can start to yellow with age due to a chemical reaction from the materials acrylic is made from. Acrylic tanks typically require a stand that will support the entire bottom of the tank, or the tank might break apart from the weight of the water. Acrylic tanks also require more support across the top of the tank or it could start to bow out and spill water from the top.

The plus side for glass aquariums is they are easier to build as they only require the glass panels to be sealed together with silicone. Glass tanks are usually far cheaper than acrylic tanks. They also tend to be easier to attach a hang on back filter, which tend to be an easier method of filtration to set up. When you are setting up your tank you will not have to worry as much about potentially scratching the tank when you are adding your gravel and décor and in my opinion in smaller tanks, the glass tanks tend to look nicer than acrylic.

The upside for acrylic tanks are that they are typically about 50% lighter weight than glass tanks. They have better insulation so they can help with your electric bill.