I've used gutter screens before. Debris gets caught in the screens and you still have to clean them off, otherwise the debris will pile up onto your shingles(?) and cause them to decay prematurely. I suspect the foam will behave in a like manner. I've found the smooth coverings that allow debris to wash off to be a better solution. They cost more but you get what you pay for. See www.gutterhelmet.com or www.leafguard.com

I don't have any experience with the flip out or the foam, but right now I am looking into a vent-like system that replaces the gutter called Rainhandler. The water rolls off the roof and then is dispersed along the ground by a series of angled vents - like a five inch mini-blind on the edge of your house.

I do garden work for a guy who has it on his house, and he is happy with it. There is no erosion in the flower beds below the Rainhandler. But he has a small house, and trees shade a lot of the roof. I don't know how well it would work in another application.