Is glass really as good as a Wood box?

No, if the fiberglass box is built up with good layers and numerous amount. Which would be 6 layers I think for 1.5 oz mat. Then fiberglass will perform just as well. I think if you are going to fiberglass something it needs to be worth the effort. Since building a MDF box is a whole hell of a lot easier. Also I cannot get bubbles out of my layers for crap!

Hey carbon I learned that if you put a good coat of resin down then lay your glass on top of it. Then put more resin on top of it, it helps get rid of bubbles also, if you cut your brush bristles down to about an inch long then that helps when you dab it to push them out. Also once you let a couple of the cure, if you're going to do more make sure there are no bumps and stuff if there are sand them off or cut them off with a dremel anything sticking up really. That holds the next layer of glass up in the air and makes it form bubbles.  So just cut those off and then lay your next layer. Learning the trade one fiberglass creation at a time!

i totally agree with what all previous posters said, but i want to throw out some common knowledge- MDF is incredibly strong on flat areas, but if you've ever tried bending it, you would see that is impossible. inversely, fiberglass is quite strong through complex curves, but in flat are as it requires much more reinforcement. both can be excelent buildign materials for sub and speaker boxes, both have their own applications. good luck to all with future glass and MDF projects. ~Ryan