If you are buying new, I do not think you could go wrong getting a
Meiji Techno microscope. You might consider a model with a standard c-mount camera port as then you can change the camera if or as the technology improves and your needs change (which Meiji Techno supports). Going with an add-on camera also tends to be less expensive.
Another approach, and what I have been doing, would be to get a good, used microscope made in the 1980's and 90's. They were much better built than what is made today (the somewhat old fashioned Meiji Techno being an exception) and if they were not abused, will give many more decades of service.
But it all depends on the application and your wishes and requirements. Could you write about what those might be? And what camera issues are you trying to address?