The Specs That Actually Matter
Manufacturers advertise magnification numbers aggressively — but magnification means nothing without working distance (how far the lens can be from the subject), depth of field (how much of the subject is in focus at once), and color accuracy (the camera sensor's ability to render colors faithfully).
For industrial inspection, working distance is the #1 spec. A 1000x microscope with a 5mm working distance is useless for inspecting populated PCBs — the components block the view.
Test Results
Best Budget: Jiusion 40-1000x ($38)
Working distance: 8mm. Adequate for PCB inspection on bare boards. Poor color accuracy (images have a pronounced green cast). Resolution maxes out around 3 megapixels. Acceptable for hobby PCB bring-up and basic solder inspection. Not suitable for quality documentation.
Best Mid-Range: Mustcam 1000x ($85)
Working distance: 10mm. Better color accuracy. 5MP sensor. The best balance of price and capability for maker-level inspection. Will handle most PCB work and reasonable watchmaking tasks.
Best Industrial: AmScope MU1000 ($280)
Working distance: 25mm. Genuine 10MP sensor. Excellent color accuracy and very low distortion. The 25mm working distance accommodates populated PCB inspection. Used by professional repair technicians and quality assurance inspectors. The benchmark for what a serious bench tool should be.