I spent part of my vacation at my mother's home in suburban Denver. She had a gutter topper installed on the back of her house and her porch, but was complaining that the gutters were overflowing every time it rained. So, I climbed up and discovered one to two inches of crud inside the gutters (mostly small pieces of leaves along with dirt and seeds and who knows what else). Her roofing guy" had suggested she get rid of them last year as he said none of them worked well and usually just accumulated more buildup than an uncovered gutter. The gutters in the front of the house without any covers were almost completely empty and worked fine.
So, my mother agreed to let me remove the gutter covers. I cut an empty 20-oz soda bottle into a scoop and used it to gather up the crap in the gutters and put it into a bucket. A couple of hours later, no more gutter covers and clean gutters were the result.
As this may be the result of the particular design she had, I encourage you to walk around your neighborhood and look for houses that have gutter covers. Ring the bell and ask the homeowners if they recommend the covers and if so, can they tell you the brand? But, I should tell you that when the gutter covers appeared with the trash, some of my mother's neighbors noted that reminded them that they wanted to get rid of their covers too (and no one seemed to have had the same model installed).
Technology does not always make things better.
Dave