I didn't think it would work. But they are great.
Yes if we have a big down pour, they can't handle it. But I have had the others and they can't handle it either and I still had to get up on the roof and clean them. The micro screen leaf filter system is the best I have had. And I have used about 5 different types of screens.
My down spouts are not clogged, I have not had run over from the drains being clogged. I have gone out in the rain to check.
Now I just have to get a product to keep the snow from freezing and running back under the shingles. I guess I will have to heat trace the gutters.