I *think* I have the technique to use the ZF2 but I have seen other people say that the LDF is more powerful. Which can generate more power on a full power smash
ZF are super stiff. If you are as good as what you claim, it definitely hit harder. Stiffer shaft harder to bend but if one able to bend it then it definitely snap back even harder which resulting even harder hitting. But for majority of people, they didnt train like a pros & had no strength for it thus using ZF would end up with no snap back which mean lower power. Other hand LDF that are more flex are easier to use so it create illusion of hitting harder.
ZF2 has greater potential for power/higher ceiling due to compact head + stiff shaft + very HH LDF has easier power access because it is less stiff, less HH and bigger head There is typically a trade-off between access-to-power and power ceiling The average shot from the majority of players is therefore probably more powerful with LDF because, relative to ZF2, it is easier to play with