Yes, major BT issues on my iMac 2013. Much more noticeable when you connect Bluetooth Audio. It's like an intermittent signal is being sent. My total conjecture on it without evidence is some attempt to implement the unlock feature or Copy/Paste constantly pinging and checking local devices. I reset the Bluetooth Module in the Debug menu (Shift+Option Click on the Bluetooth icon in the menu) and it helped for about 10 minutes.
Please fix in beta 2!!
EDIT: Also worryingly happens in boot camp which makes me think it's a firmware issue.