I have only just begun using Litchi with my iPad
Air 2 with approximately 90 minutes total flight time using it. Also note that I have approximately 20 minutes flight time using the DJI GO app, so this is an indicator of which I prefer in general... I have only used two of Litchi's flight modes thus far: FPV (First Person View) and Waypoint.
FPV is pretty much what you get with DJI GO. Everything on the remote works the same, and you can fly around and have a grand old time.
Waypoint mode is what attracted me. In this mode, you are able to autonomously fly a pre-plotted mission from takeoff to landing - all with the simple touch of an icon on your flight monitor if you want. I generally perform the take off and landing though, meaning that I manually get the craft up to an altitude that is close to that programed for its first waypoint, and then I press 'Start' to begin the mission. It will ask for confirmation, and once given, it will load the flight plan into the craft, and off it will go on its own. After reaching its final waypoint, I have my action set to Return Home, but as it enters this mode, I generally take over and manually fly it back. During the course of its waypoint flight, you can also set up 'Points of Interest' (POI) along the way, allowing you to program camera actions like take a photo or capture video, or, of course, you can just capture video of the entire flight and have the camera aim itself where you want by setting up which POI's the camera looks at during each portion of the flight. I guess DJI GO allows you you to do something similar to this as well, but only after you have already manually flown the mission and saved it for a future flight.
One other thing that I really like about Litchi is the fact that it gives you numerical percentage readouts for your Remote and Video Feed connectivity - rather than the bars that DJI GO gives. For some reason, I greatly prefer this percentage readout for that quick glance when flying to a distance.
Lastly, I want to add that I am not belittling DJI GO in any way. It is a very powerful and intuitive software app that has its place for sure. I just like having that little bit extra to do with my copter, and Litchi's waypoint mode offers me a function that makes this hobby all that more fun and interesting.