If you are doing materials work you will probably use a research inverted without a transmitted illuminator. This setup used to be called a metalagraph. However in todays materials scene were a metalurgist may be looking at carbon fibers and the microscope being used is the same frame as a biologists I feel that the term is outdated. The three size differ in price, capability and illumination. Bench top and research microscopes are Kohler illuminated while most student microscopes use diffusion illumination.
Student microscopes are the smallest and least expensive of the three.
While student microscopes can be used for advanced techniques and documentation they do not do these things with ease or grace. They are designed for bright field and phase and to be used by students. This means that they have to be rugged and simple to use. Student microscopes are sold primarily to schools, no surprise there. They also make very good doctors office microscopes since they are simple, rugged and cheap.