I like Yosemite, but that doesn't stop me from being genuinely astonished that it has made it into the current build with such a glaring (at least to me) slow Wifi issue. Download speeds always hover just over 10 Mb/s on both my Retina iMac and 13" rMBP. Researching a fix I came up with the command sudo ifconfig awdl0 down and this brought the speed back to what it should be. However, it is only a temporary fix and leaves me with AirDrop which only works in "Older Mac" mode. Is there a more permanent fix to this that doesn't partially disable AirDrop?