I fly mode 2 as my primary mode but I can also fly mode I and I have done so many times. Because I have flown both modes I can tell you that mode 2 is the best way to go. A few of the many negatives of mode 1 are as follows:

1. Mode 1 flyers have a harder time retrimming in flight because they must stop using one of the primary flight controls, e.g. aileron or elevator to trim.
2. The throttle stick must have a firm click steps between RPM ranges to keep from having engine speed changes during aileron input. This is very problematic on landing when the engine speed should be controlling decent. Some mode 2 flyers like me remove the throttle stick detents completely for a more liner engine speed control.
3. The position of the aileron stick keeps changing every time the throttle is changed. This makes the aileron input more difficult.
4. Coordinating the aileron and elevator for smooth maneuvers is really hard. Try a smooth approach to a landing using mode 1 and you’ll see.

Bottom line, mode 1 is a just left over from the days of the Stone Age reed radios and is mostly used by the old “gray hairs’ :-). Remember if mode 1 was the way to go the 1:1 aircraft would be that way and they aren’t.