MU500-HS: High speed with very good image quality and resolution.
Previously owned the 1.3 megapixel MU series camera - the frame rate here was slow, even at 640x480 resolution. This made any operation that including moving specimen/object of interest tedious. Also any image operation, such as measurement, color & white balance, also slow.
By contrast the MU500-HS is a joy to use - fast frame rate even at high resolutions, and surprisingly much better image quality than my previous camera. Frame rate is *almost* as good as dedicated HDMI camera - which allows for image inspection and realtime viewing, for example soldering PCB.
For my purposes, don't need anything better and very pleased with performance.