I have been using CarPlay via an 8000NEX headunit since 12/14 and unfortunately CarPlay has been the buggiest software I have EVER used.
I use CarPlay for everything except directions and when CarPlay works it's a thing of beauty - a clean and elegant extension of iOS on the Pioneer headunit. But for whatever reasons apps and Siri constantly stop working, or work erratically, and more often than not the only way to fix this is by restarting the phone and/or restarting the car (as the Pioneer doesn't have a reset feature). To give you an example I'll share what happened just last night -