I'm the owner of a 2013 P85 that we purchased last year through the CPO program. It was loaded with pretty much every option available in Feb 2013 except the rear facing jump seats. We love it, and I'm thrilled about the warranty, which we have used.
We just had a loaner 70D for 4 days and about 400 miles. It was equipped with Autopilot hardware, but the Autopilot was not active. Without the Autopilot, I preferred our P85. Our car definitely feels more spirited and performance minded.
I have driven Autopilot equipped cars, and the system is amazing. As a technophile, I'd spring for the 70D. As a car enthusiast, I'd spring for the P85. As a Tesla owner who financially stretched to afford our car, I'd spring for the car with the warranty!
In practice, the P85 is probably going to get you about 20-30 miles more range than the 70D. Over the 400 miles we had the 70D (in almost all weather conditions, including snow, rain, cold, warm and dry), our energy consumption was around 370 wh/mile. Our P85 in similar conditions gets around 340 wh/mile. (I know they say the 70D is more efficient, I'm just reporting what I observed.)