stated are very effecient and do a good job IF you keep the debris out.
Rain dispersal systems are, as jb said, a gimmick. All they do is to break up the water a bit and spread it out, so what is the big deal.
Get good seamless gutters, with good down spouts and extensions going away from the foundation and do not put those screens on the gutters either. They keep the trash out and also can build up a layer of debris that won't allow the water to enter and then its over the side again.
Just every Spring, clean out the gutters.
Also one other point, but seamless and get the color you want to match your home. Then don't ever paint these gutters, the baked on finish is super and does not need painting ever.