I bought the Cooler Master U2 (2 fans) to cool my 3 month old laptop; Lenovo Y470. Unfortunately, it did not cool my laptop at all. I don't think the problem is the Cooler Master though because I've read reviews where it cooled down other laptops by 3C to 5C. I think my issue is the internal design of the Y470 which somehow blocks the blown air from reaching the CPU and GPU. I would open up my laptop to investigate, but that would void my 3 year warranty.
I bought the Cooler Master because the movable fans allows you to place them directly under a vent.