Screw cheaper. How's about quality. Can you build it yourself the right way??? If you do decide to do it yourself why go glass. Accrylic is very easy to work with.
Yeah quality is what you pay for if you were to buy a ready made tank ! So if your building it your self you better make sure that you use the correct thickness in glass and make sure you use the correct silicone to stick it together.
I hate handling large sheets of glass if I ever build my own glass aquarium I would fill it up with water and leave it in the garage or something for 2 weeks to make sure it has no leaks and that is can hold water.
i looked at building my own and its simple to do if you take care but for the cost of the glass and the time it would take to build 6 tanks it was way cheaper to have them made for me to order.