Depends on how much you want to spend. I believe acrylic cost more. I had a 150gallon glass aquarium and the silcone came apart while i was cleaning it out and it leaked luckily it wasn't very big leak. With acrylic their are no seams so you don' have to worry about leaking, but they are very easily scratched. Glass you dont have to worry about scratching, so they both have their pros and cons, but mainly the price. Hope this helps you out.