I had Leaf Filter installed a few years ago, and just this summer discovered extensive structural wood rot on my home on an inside corner (where there is a valley in the roof), caused by leakage out the back of the Leaf Filter gutter protection system onto the roof decking below the metal valley.
Leaf Filter strongly promotes their product - and true to their guarantee - the gutters don't clog...but in fact, Leaf Filter puts the "clog" on the TOP of the gutter, and by adding corner splash guards (to keep water from overflowing the LeafFilter at inside corners (valleys) leaves back up behind the splash guards. That isn't the problem though...the problem is that Leaf Filter DOES NOT SEAL the inside corners.
So - when leaves - and water - back up behind the splash guards (both ON TOP OF THE GUTTERS) - it is easy for the water on top of the gutter to flow backwards through the seam in the Leaf Filter on the inside corner (and under the metal valley flashing!), running down the wood decking and down the walls of the home ... to slowly rot away the corner of the house.
In my view, this a clear defect in the LeafFilter system and system operation.
The damage to my home will cost me far more to repair than it did to have LeafFilter system installed.
I should have simply paid someone to come to my house to clean gutters once per year...or done it myself as I used to do... Now, I will have to remove the expensive LeafFilter system, and then repair the damage, and still pay for once-per-year gutter cleaning.
User's recommendation: I strongly recommend that you NOT purchase LeafFilter, particularly if you have inside-corners in your roofing/gutters.
Monetary Loss: $10000.
Preferred solution: Full refund.
Location: 2885 152nd Avenue Northeast, Redmond, WA 98052