I have leaf guard and they do not work. I replaced some of my gutters because the leaf guard ones simply allow water to roll over them and onto the walkways, deck, etc.
Total waste of money. If you don't want your gutters to collect leafs, just don't have anything at all as Leaf Guard is about the same.
If you really have to buy these, make sure they tell you how the corner gutters are going to work. Also ask them about how they change colors to the share of your shingles. They don't rust, just look like *** after a year or so.