Let me clarify it is very simple and straight forward to use. However for it being the “better” “newest” module, the app definitely has some catching up to do. First & foremost the app will NOT open on my work tablet. (Samsung) luckily it did work on my iPhone so I was able to continue with the job. However the app & user manual lacks critical information that the z200 app/manual has. For example the module location, the z300 gives a numerical value of the Riso location but that’s it. The z200 would tell you the fault location between modules (x and x). This app doesn’t even tell you what PV terminal (+ or -) the Riso location is counting from. The z200 tells you in the user manual it counts from the PV+ terminal. I had to do some calculations of a captured fault to determine the z300 counts from the PV- terminal. My formula was spot on with the Riso fault location value the app provided as well so this confirmed the PV terminal location where the module count started. Also the z200 app told you what kind of fault it was as well as what terminal or home run was affected. The only functions of the z300 in the app are string tester & toner. The z200 app had much more options, information & the interface was much user friendly. The z300 is much faster in detecting the Riso fault and in my professional opinion is more for a skilled & experienced operator who’s pretty intuitive to solar panels and ground faults. Or team of operators that can access the recommended Riso location value and approximate what modules the fault is between. The app isn’t as easy to navigate and I wouldn’t recommend my technicians to use this machine & app over the z200. Due to their skill level & expertise. Again I can use it just fine & had to do some research online and offline to correctly determine what the PV terminal it was counting from as well as a few other things the user manual and app could have