The downside of the ferry is that it is a trek from either the airport or the train station in Naples AND a trek to the hotel in Sorrento (the Sorrento Circumvesuviana station is much closer to the hotel). Taxis in Sorrento aren't such a big deal - $10 tops so just arrive - taxi to the hotel - and walk the rest of the time. Taxi back to the station. You'll be happy and not too much poorer

As for the hotel - great - loved it. Wonderful views, staff, exec lounge, pools, etc. Well worth the vacation!!!