I'll just pile on here as another victim. iPhone 5C IOS8, iPad Air IOS8, 1 year old iMac/Yosemite & mid-2010 MacBook Pro 13"/Yosemite.
Initially everything BUT the phone would ring, but I could not answer calls on any other device (I tried every available button), and a notification would stay on the MacBook Pro's screen until I "rejected" the call - usually 15 minutes later.
Phone is not in Airplane, muted, silenced, do not disturb or any other mode. I rest ringtones - they work fine. I get calls - nothing except a VERY short vibration; even if I see it I have no time to answer. I'm trying to find an automated callback system so I can keep trying things but no luck yet, so I have to have a friend call me to test it.
I went back through the feature announcements for both operating systems and saw nothing about computers taking phone calls or messages, nor do I WANT them to. But I WOULD like my phone to ring, just like a real phone!
So far I have not found a single "feature" in IOS8 or Yosemite that is useful, saves time, or does anything but look pretty and foul up day-to-day activities (and the new Safari is absolutely awful!).
What the heck is Apple thinking? But for now - HOW CAN I GET MY PHONE TO RING AGAIN?
I was planning to "jump" to a 6+. Fat chance now.