@mian yeah people hated trying to program it because of the UI.
i never used one directly (though i think my piano has a dx7 core built in, you can't program it on device) but my issue with FM is most of the time when you try to explore with it you just get garbage
i've been following some videos where they build up the patches. the patches sound really nice, but if you just flop random knobs you tend to get trash