Manual mode does not mean the same thing on different controllers. Manual in the DJI world is the equivalent of 'Acro' in the APM world. On some controllers, I suspect most, manual would be equivalent to Atti in the DJI world. GPS mode on APM is 'Loiter'. Pure manual control is what you would use to do acrobatics such as loops etc. It's where the autopilot won't stop you from doing anything. That's why you think manual mode in DJI isn't smooth and is hard to fly. I suspect the manual mode you use on other controllers is still maintaining attitude and basic flight characteristics. What they call Atti on DJI and 'Stabilize' mode on the APM world. Hopefully I've confused the matter enough now. Just make sure you can fly the copter without the aid of a GPS mode and you will be fine because sooner or later GPS will either become unreliable or fail altogether.
The "manual" mode on the Hoverfly controller is a true manual mode, in other words there is no automatic leveling or any other flying aid. The Hoverfly does have an automatic leveling feature called horizontal mode, and that does work like DJI "atti" mode, but that is a separate mode than the manual mode that the previous poster was referring to.
The main issue to consider is how the flight controller is actually using the signals from your transmitter to control the aircraft. For example in auto leveling modes (like atti on DJI, or horizontal mode on Hoverfly) your transmitter is basically controlling the multicopter's
angle directly. But in true manual modes your transmitter is controlling the
rate that the multicopter is changing its angle.
Manual mode (rate mode) is very desirable for aerial video because of the way the control loop works. For example for forward flight you would move the stick forward, and once the multicotper is tilted forward to the desired angle you return the stick to neutral, and then you are able to make very small and precise corrections from the neutral position to guide the craft on a very smooth flight path. In angle mode (atti, horizontal, or gps modes), you must hold the stick at the position to keep the craft tilted at the desired angle. If you return the stick to neutral the craft will level (or stop in the case of GPS). This is not ideal for filming because it is extremely difficult to hold a very precise input on the transmitter to keep the multicopter set at a very stable angle. Also you are not getting the desired effects from exponential settings in your transmitter. You may think you are good at holding the stick at precise setting until you try Hoverfly manual mode, and then you will see how many undesired movements your multicopter was actually making.
I've flown all the major controllers and I agree with the other posts in this thread and other threads, the Hoverfly in manual mode offers the smoothest response. Manual modes on other flight controllers don't seem to work as smooth. It seems the controllers from DJI are designed around being primarily flown in Atti or GPS modes. There are certainly benefits to leveling and gps especially when flying at long distances, and with the advent of brushless gimbals the smoothness of the controller is slightly less critical.
