Last week we followed through on our plans to pick up a rental car in Rome, drive down to Sorrento, and then to drive the Amalfi Coast.
The traffic was OK, we didn't get horrendously lost, we enjoyed the trip from Rome to Sorrento, and last but not least the Amalfi Coast is not scary or steep or any of the other things that we expected. It was the same sort of twisting, curvy roads that you drive along the France/Spain coast or driving up to Peillon in France, or in some mountain ranges in the US. We didn't find the Rome or Naples traffic to be especially bad either. It was the typical big European city traffic that we've driven elsewhere. The one lucky thing for us on the Amalfi Coast drive is probably that the traffic was relatively light since we are off season. We also had an automatic transmission so no gear shifting was needed.
For anyone who has considered driving but was convinced to take public transportation instead, you need to know that it is extremely do-able. And enjoyable! I couldn't imagine not having the freedom of our own timetable and being able to carry on conversations in the car. Plus we could load our shopping in the trunk.