In response to JimK45. There was a test conducted on build up specifically. It was done by CONSUMER REPORTS. They rated GutterGlove #1 They tested for about 480 days and GutterGlove scored perfect in Heavy Flow, Severe Flow and BUILD UP! I work for KTM Roofing in Atlanta and we install this product all the time. It really is a great product and I have received great reviews from customers who had horrible leaf and pine straw issues before install.
It would be helpful to see the guard function with some (lots of) leaves and litter. An issue is how well it cleans itself so it continues to work.
Nice looking product. I seen some this weekend at a home show in Hamilton Ontario this weekend. Feels very well built.