I think it depends on:
1. Hardware , I don't know why, but I can't use fw 400 because it is drive my mavic crazy. My gimbal dance and become very hot after start up. My brand new mavic is preinstalled with 500 fw though before.
2. Pilot. I'm happy enough to update 2 times after I received my mavic combo and i'll never upgrade above 700 again. It's enough for me to take photos, and it's enough for me to take videos. No matter how good new firmware is, it's limited by the hardware which is mentioned in no#1. Eg: camera spec.
So my conclusion is, no matter which firmware do you use , eventually it depends on your own situation and devices.