We did a Norwegian Grand Mediterranean cruise in September 2016 and did 3 shore excursions with CRUISING EXCURSIONS.
We were nervous not having done shore trips with anyone but the cruiseline before, but Norwegians shore tours with basically the same itinerary were about 40% dearer than CRUISING EXCURSIONS.
We would like to recommend this company - excursions in NAPLES - Sorrento and Pompeii 8 hours, MYKONOS - walking tour and bus tour of the island - 4 hours & ROME on your own - coach transfer from Civitavecchia 8 hours. They were on time, signage made them easy to find once off the ship, guides' English was good and they had good local knowledge. Payment was online. They only thing to watch might be the cancellation policy as there are penalties in cancelling once your ship has set sail. JoyfromOz