The Best Microscope

The best microscope for you is one that will do what you need it to do, even as your needs change.  This generally means that it will either have the best optics you can afford in the objectives and the condenser (the eyepiece is much less important, but highly corrected objectives often need special eyepieces to finish the correction).

You might be surprised at how modest a microscope you can buy that will suit your needs.  As your needs change, an upgradeable microscope can change with you.