This topic is close to home for me. A year ago I installed the LeafFilter brand gutter covers on my house and they flat don’t work. I live under fir, cedar, oak, cottonwood and maple trees. The screens clog and water flows over the edge. LeafFilter added new downspouts, put up sheet metal diverters, changed screen sizes, twice, and sent cleaning crews multiple times. Still don’t work. It would have been cheaper to call a service company to clean the gutters a couple of times a year.
After my unsatisfactory experience I talked to a couple roof and gutter companies and they don’t recommend any of the covers. They all have shortcomings I was told. So, mine are going to go.