There are many types of music stands available, from the old wire fold-able stands that are reminders of middle school band practice, to dual shelf plexiglass thrones. Their are three types of music stands when it comes down to it;
Trigger locks: These stands have their height controlled by a trigger lock just under the music holder. These are a personal favorite because they are easy to use, can hold a lot of weight, and never seem to loose their ability to hold to the weight.
Sliders: Ok, that's what I call them. They have no means of outward mechnical adjustment such as the trigger lock. You heighten and lower by pushing down ot placing your foot on the base and raising up. I have a sheet music book so big that if on one of these stands, a little downward bump can lower the mic.
Nut and Bolt: These stands have height controlled by turning a large nut that tightens the grip around the pole. These are ok for adjustment but I have had times where it seems that no matter how much I tighten them, they lose some of their grip.
Regarding the construction material, most are some form of metal alloy. There are also PVC (read plastic) models as well as wooden models. Having used wooden adjustable stands, I've found their fault is in the mechanism that adjusts the tilt of the music holder. Thus with too much weight, they tilt down and your stuff falls off.
Music stand makers include: Giardinelli, Hal Leonard, Hamilton Stands, Hercules Stands, Manhasset, ProLine, Prop-It, Stageline, and Yamaha