I am an older (retired) owner of a P3P and would like to know the advantages or disadvantages of the Litchi app.  All information would be greatly appreciated.
Thank you.

I use Litchi for waypoints flights all the time.
You "draw" the route using your phone/tablet/computer, very easy to use.

Track mode is nice too.

DJI Go I use only for settings.

I really like using the Mission Hub, being able to set up flight missions in advance.  Once I'm on site, I let the mission run, which normally allows me extra time afterwards on site.  The new VR mode is cool too.

All of the above,

Plus I like the girl's cute voice who constantly talks to you during the flight. My wife is getting jealous of her!!

Litchi
1) allows for you to create mission on your own time (me while at work). The DJI APP only allows you to create waypoints if its in the air. If you create missions just know that you have to log off from the computer before logging onto the app for the mission to pop up.
2) FPV, which is awesome with VR goggles and can be bought on ebay for $20.
3) Pano, press it and the drone takes over create a panoramic picture

The big advantage I love is #1. Setting up a mission at home or work on a computer is great and also fun. I have made alot of videos and the video is much smoother. Its a proven app to so don't need to worry in my opinion

Heres is what I'm talking about. Also when it was on the field simulating someone running that was me and not the app. This one had over 30 waypoints and only took 5 minutes.

I you tend to use automated flying a lot more, the Litchi is best. For just manual flying, the DJI Go app is better. The 32 channel hack only works with the DJI Go app. But I loved the included free flight log feature though. You just uploaded it from the app and see everything at the healthydrones site. It's only $22......buy it already.....

Just to add..
FPV with full tracking. Look up down left right...
Pano mode for 360x180 VR (requires stitching program).
Full follow mode (heading and course mode).
Has Focus mode
Has App Tracking mode like the P4 (performance may vary depending on your device).
Has Leash (follow another gps enabled device)

The only thing it cant do is the gimbal and IMU calibrations and FPV recording.