I use the Android version of Litchi which has more features than the iOS version (so far)... with iOS you only have access to FPV and GS modes (plus Mission Hub) but for the same price point... I'm not sure what the in-app purchase of $5 buys you in the iOS version... in the Android version, it provided access to Panorama and Focus modes but those aren't available yet in iOS...
I've heard that Autopilot can be much more complicated to learn but YMMV.
I've found that there is no single flight app which covers everything I want to do... so am using DJI GO, Litchi, Vertical Studio and Hivemapper so far... each fills a need or desire...