Well, a lot of DDK mains seem to think that Reflector and "lasers" are what destroy Diddy. Well, they don't know that SHDL is highly punishable by a banana throw, that Reflector is highly punishable by a very simple mindgame (you have a banana, you approach falco. If he throws his reflector, shield, jump, side B... This puts Falco in a disadvantage position).
About "lasers", i can only see a retreating SHL to be annoying for DDK. But here also, if you throw a banana under Falco while he's jumping, you have the advantage.
I played a good DDK here, who knew the Falco's match-up very well (he plays the other good falco in paris very often), and i get 2-stocked.
Falco can also pick up bananas, and this is very annoying for a DDK (i comboed this ddk main with bananas lol XD). But this is true with every character, not only Falco. And good diddy mains will be careful to not throw bananas mindlessly.
So 50:50 or 55:45. But there is no way this match-up to be 65:35 imo.