It's a matter of timing more than anything else. If you are ready to buy a new car right now there is no reason to avoid a 991 just coz it's a first year model. If you were planning to buy a car next year or later, there is no need to accelerate your decision just coz the new 991 is out.

 

Less worried about first year issues, more worried about 2nd year improvements!
All cars have issues and time is an important factor. More so in the 1st year you get quirks vs problems. Like the Jag XK came with an retractable antennae in the first year vs windshield antennae in the second. Or the new PCM in the cayenne, it wont show the time on the first year, you can change it on the second. Minor annoyances and not enough to deter me. You could always go for a short term low mileage lease if you are truly concerned, and jump into a full blown purchase when turn in time comes. Or just buyout the lease.