A few months to go before hitting 10 years, but my 2014 P85 is also still a great car on its original battery. The drive unit was replaced twice in 2017 under warranty, and so far, the third drive unit has been perfect. 62K miles. 252 mile range at 100% charge (when new, a full charge was 265 miles, so range is 95% of what it had originally.) Some minor annoyances, including squeaks and rattles, but no noticeable degradation in driving performance.
One thing that has changed, though: since the battery is "older," its max charging rate is capped and I'm lucky to see anything over 72kW speeds at a supercharger. It will drop pretty quickly down to 60kW and lower, under the same conditions where I used to get over 100kW in the early years of ownership. In practical terms, this means if I'm on a road trip, I need to charge for ~1 hour instead of 30-40 minutes to get the same amount of charge.