I'm running the public beta of El Capitan on a late 2008 MacBook Pro with only one issue so far. After the last update (4th) as soon as I go to Amazon.com on either Safari or Firefox my computer freezes up or becomes so unresponsive it's unusable. I've restarted every time so I don't know if I could wait out whatever is going on. It does appear that the area below the search bar where products cycle through is breaking up and may be the culprit. Any suggestions would be appreciated.