A good microscope will have a mechanical stage. This allows precise movement of the slide on the stage. A mechanical stage with rulings on it will allow you to write down the location of some interesting part of the specimen, and find it easily the next time you want to view it.
A mechanical stage also makes it much easier to create panoramas, to get a wide field of view even at higher resolutions.
Note the rulings on both the X and Y axis in the photo above. In the lower right you can see the adjustment knob, and some of the rack and pinion mechanism it uses to move the stage. There is also a spring loaded slide holder that ensures the slide will always be in the same position on the stage.
If you are going to be using the microscope for any length of time, having the stage controls low down to the working surface allows you to rest your arms on the table as you move the slide around. This makes using the microscope much more comfortable.
Coaxial controls (where both the forward/back and left/right knobs are on the same axle) reduce the amount of fumbling around for the controls, and allow you to keep your eyes looking down the eyepieces instead of looking for the stage controls. You can keep your hand on the controls, and operate them with one hand. The other hand can be used for the coaxial focus controls, so all the controls are available at once without looking up.