Trimming the trees? Excellent idea. Prevent as many leaves from coming in the area as possible. Gutter guards/screens are also a good idea, but these too need maintenance and cleaning periodically but would definitely help with the clogging situation.

By all means stick with the metal materials, those are definitely superior to plastics in terms of function and durability. I just brought up the plastic flexible type because they're cheap and easy to install, which is the kind of job that most DIY'ers tend to gravitate to. But if you have the option of going with zinc/metal then yes go with that.