There are several advantages and disadvantages to choosing acrylic aquariums over glass aquariums.

Disadvantages of Acrylic Aquariums

The main disadvantage of acrylic aquariums is that they are much more easily scratched than glass aquariums.

If you do scratch them, there is a buffing system available to help polish out the scratch. But, it is fairly difficult and time-consuming to use, and you're supposed to drain the tank when you do it. So if you've already got the tank stocked, and you scratch it, then you need to take everything out, drain it, and repair the scratch.

So it's best if you can avoid scratching acrylic aquarium's altogether. However in practice, I've found that it's nearly impossible to avoid some scratching. Even if you don't accidently scratch it moving around live rock or corals, the inside of the tank will eventually get coated with calcareous algae. This is abrasive, and removing it will often scratch the acrylic.

Advantages of Acrylic Aquariums

One of the main reasons that a lot of people choose acrylic over glass aquariums, is that it seems to be clearer and have less distortion. Aesthetically, many people including myself, think that acrylic is more attractive.

Another great advantage is its it's much easier to drill a hole in an acrylic aquarium than a glass one. On several occasions I had to drill acrylic tanks, with standard wood hole saws, and was able to do so without breaking the tank.

If you do happen to break the acrylic tank, it is also fairly easy to attach another piece is acrylic to it using a common organic solvents such as methylene chloride. The two pieces actually melt together and form an excellent seal, much more permanent than using Silicon on glass. Although it may not look pretty, it will be functional. But I still prefer glass aquariums because they are cheaper and more scratch resistant. There are other advantages to glass aquariums which can read about in that section.

Best choice for Beginners

As a beginner, it will probably be easier to go with glass rather than acrylic, but check them both out together in your local fish store and see which one you prefer.