Quality of bongs

Many people ask if all bongs aren't really the same ... In the end both a standard bong for like 20$ and an expensive roor bong will give the same high effect.
What makes expensive glass bongs worth the money? Is it just all the accessories, extra diffusers and ashcatchers?

In short, it's not the extras that make the difference, and yes the difference between quality bongs and standard models are huge:

Joint size, glass type used, shape, joint connections, basic volume, glass quality, glass on glass. All those things and more make a huge difference in how bongs function. There really is a lot of engineering goes into some high end glass. You may be able to find something similar, tip it over once though and it's a pile of shards. Some of the nice borosilicate pieces are more durable than some furniture.
Also an inexpensive piece may have a huge amount of drag, when you hit it you have to work too hard to do so and it's just uncomfortable and discouraging.

It's true that bongs can be expensive, and to many light smokers, expensive pieces might not be the most ideal investment. There is no shame in buying a cheaper bong if your goal is simply to get high. But for those who are looking to get more out of their smoking experience, there is an undeniable advantage in buing high quality glass, precisely manufactured, low drag, unmatched smoothness bongs.

Then there is just that subtle something that unidentifiable but truly there none the less.