I purchased these for much less per light and am very pleased with their output. I mounted them by drilling small holes through the top of my gutters and using some small nuts/bolts. I highly recommend them; aluminum casing instead of plastic, completely weatherproof, 16 LEDs that are very bright and the motion sensors work well.
They remain on in a dim mode (think strong moon light) as soon as it gets dark out and activate when someone gets within 10 feet or so.