I haven't switched one system to the other, but I have owned both on different boats. Both performed perfectly.
With any electronic control system, I think there are two very different "packages", and I'm not sure which the OP is struggling with.
On all of them the shift controls and master control box is the same, but how it then controls the engine and gear can be quite different. In both of my boats, the engine and gear were electrically controlled, so there was nothing more than a cable between the control box and the engine and gear. This requires that the engine throttle be electrically controlled, and that the gear control is via solenoids.
On engines and gears that are manually controlled, there are servo boxes for the engine and gear that mechanically control the throttle lever and/or shift lever. I have never owned on of these, but they seem to give you both the best and worst of both worlds. You get the operational convenience of electric shift and sync, but you get all the problems of electric controls PLUS all the problems of mechanical controls. Loose shift cable, or poor adjustment can cause all sorts of problems, in addition to any electrical faults. And to synchronize, presumably the control system needs a reliable tach source from each engine. I don't know how that's handled and is probably very boat-specific.