“Not ideal if you plan on running the Pi in a room which you use. Gives off a high pitched and annoying noise. I ended up getting rid of the fan and buying an aluminium heat sink style case for the Raspberry Pi instead.”
“Does exactly what is says on the tin. Keeps the Pi cool. A bit whiney when it's on full speed, but rarely needs to ramp up, and I hardly ever hear it. Not really beefy enough to help with overclocking but prevents any throttling at the stock clock speed. Can't complain at the price either.”