We ended up using DriveAmalfi on our journey from Napoli Airport to Praiano and back. 110 Euro per leg per car. Great service and all drivers speak English/Italian and some even Spanish!
Don't rely on buses! After spending 10 days at the Amalfi coast, we've learnt that you should only use them if you have plently of time to spare.
It's about a 5-10 min walk.
When we returned, we took a Sita bus from Praiano to Amalfi which takes you straight to the port. There is no going up or down stairs at the port. We purchased a ferry ticket for the fast ferry (35 min) approx an hour before departure while you can purchase up to 30 min prior to departure. No refunds if you purchase your tickets way in advance if the ferry gets canceled. Ferries do cancel dependent on weather. Once arriving, it's about a 5-10 min walk to the train station.
I agree, if you are short on time, use a private driver. We used Mandara Car Services and paid 110 euros for 2 people and luggage: mandaracarservices.com. A friend who used his service previously had a English speaking driver however we did not. It did not matter since we were too tired to talk after landing in Naples.
We used city airport taxi web site 5 people in a 8 seater van due to large amount of luggage
130 eu driver was waiting in the airport
To easy excellent imo