Hi Yosemite really screwed my Macbook Pro 15" 2012 wifi connection. Connecting to the wifi is very slow, often fails. Then, wifi randomly stops working, sometimes i get a beachball and safari becomes unstable, the only fix is to disconnect the wifi and re-connect it. Airplay video performance is terrible, with very slow framerate and butchered sound. Problems appeared as soon as i installed Yosemite, and haven't been fixed by 10.10.3. I've installed Mountain Lion on a separate partition, and wifi is perfectly fine here, so is Airplay. Maverick was also fine, never had a problem. Any help ?