Modbus Poll is the default tool for anyone working with Modbus devices, but it hasn't changed much in years. You get two color rules per row, no SCADA layer, and a license fee for every machine. mbSCADA is a clean-room reimplementation built for people who want more control without paying per seat. It's for automation engineers, embedded developers, and anyone who needs to poll Modbus/TCP, RTU, or ASCII devices and actually see what's going on.