617fan
US Veteran
The only guard that actually works IMO is this "gutter stuff" which we had installed a few years ago. It really works. At first I thought that it might slow down the flow of water but it doesn't. Not one leaf gets through. Although we had it installed when we replaced our gutters, Costco does sell it as a do-it-yourself package - a little expensive, but worth it!
Costco - GutterStuff® Self-installed Gutter Filter
I was also intrigued by this but hestitated because I feared the large white oaks surronding my house drop alot of "flowers" in the spring that clog up my gutter guards. I was afraid that stuff would stick in the foam and I would have stuff sprouting in the gutters. I love the shade but trees sure can be a PITA.