Jeff,
The blender jar is made of plastic. I was skeptical about it at first, but I almost think that it is better than a glass jar. It is of very good thickness, and does not feel cheap at all. It almost feels indestructible. Because it is plastic, it is fairly light weight, and does not shatter in the event it is dropped.
To answer your question about how loud it is, I would say it is as loud as your average blender on low to medium speeds. On high speed, it is about as loud as a shop vac. This is probably louder than some may prefer, but keep in mind that you usually only run a blender for about 30 seconds at a time.
Evan