I have the 760 JPI with Gami injectors.
The issue with steam gauges is that the EGT probe is fitted to the commonly hottest cylinder, but this is not the case on all engines, so you may be evaluating on one cylinder where another one runs hotter.
The JPI will allow you to view accurately all cylinders and set parameters for warnings.
Mine is with the fuel flow and it works fine (on a seneca) because i tend to fly long legs and once leaned in level flight (LOP !!!) i don't touch it anymore unless i see an issue on temperatures.
In all i think it helps me to better estimate my fuel flow as well as manage my engines better hopefully leading to a longer engine life and safer flight.
I ve had one probe which was faulty early on, no issues since (1 yr)