As I said I haven't flown the 12 C, so all my info is second hand. The Navy replaced the 12C with the E in 1963 when I learnt to fly and did a huge 50 hours on them and naturally found it difficult. In cool climates and low altitudes, the 12E outperformed the Bell 47, hence they were used for sling work in New Zealand and crop spraying here. Why is it better than the C? I can't be more specific other than to say it is newer, any C must be at least 40 years old. Management Aviation ( Bond) used Hillers in Cambridge for spraying, so someone there may know more.