I assume the 2014P85 does not have autopilot hardware. If it does, the 2014P85 may be a fantastic purchase... besides that ..
My suggestion: If you can, wait for the Autopilot rollout, delay your purchase -
especially if Autopilot is important to you. Ask Tesla, as a potential customer when Autopilot is expected to help make your decision (and please share with us what they tell you).
As of today, the CPO's give you 95% of what new Tesla's give you, for 70% the price.
If Autopilot rolls out, and is all that it is cracked up to be, then of course new will be far nicer to have.
I went through the same dilemma. I ended up getting new 70D mostly for Autopilot.
I am quite disappointed that they haven't rolled Autopilot out yet, and given their latest comments, I wish I had gone the CPO route.
Here are a few more points to consider,
1.
TACC is nice, but when there is sudden change in temperature (going from garage to outside), the lense in the camera seems to get some condensation, and you loose even normal cruise control. Of course this is something that a future software release could fix (give us normal cruise when TACC is unavailable). However, when TACC works, its rather nice. Other than condensation, a bug hit on the camera area, dust, salt/snow, etc. a number of things break TACC. It's very finicky IMO, needs perfect conditions to work nicely.
2.
The parking sensors -
DO NOT buy a Tesla without them. The car is huge, repairs are expensive. That makes parking sensors essential.
3.
The "P" part, well, I'm not a speed monkey. 70D is plenty fast for me. I'm more about a quiet comfortable ride and latest technology.
4.
The smaller frunk, ensure you are ok with it. The car has loads of carrying capacity, so frunk was unimportant to me.
5.
Range, difference between 70D and P85 is so minor, IMO it is not a consideration.
6.
AWD, is nice. Think snow, rain, mud, better handling in general, better regen. I have driven RWD and AWD in Norwegian snow. AWD can upwards climb on a 30 degree incline in 1 foot of snow. No way a RWD would do that. I know not your situation, but still!
7.
Speed limit sensing, is also very nice to have. Needs autopilot hardware.
8.
Blind spot warning, is also very nice to have.
9.
Auto headlights, are also nice to have especially if you drive a lot of backroads at night.
10.
Collision warning, is also nice to have. .. #9 and #10 will save you from deer hits. Where I live, we have more deer than people
.
#1, #7, #8, #9, #10 - require autopilot hardware.
Good luck!