MDF isn't great but is very benign in terms of not contributing anything particularly objectionable. Glass on the other hand isn't great either but is very hard and not very well damped at least if it is plate or tempered as opposed to laminated. With both (and with everything) how thick and what shape matters. But hardly anyone ever gives any thought to that. Instead almost always these things are made about as thick as you're talking, without ever doing any listening tests, simply because it looks about right for a shelf and they know that no matter what people say in reality they buy based on looks.
So which one looks better?
So which one looks better?