We spent two nights in June on the "cement dock" and really enjoyed the convenience to downtown. There is a great French pastry shop around the corner and dozens of wonderful restaurants and museums in a short waling distance. The marina had coffee and donuts in the morning and an active community of boaters. The showers, bathrooms, and laundry facilities were clean and reasonably maintained. Overall, a great place to stay for a visit to Salem.
Wonderful harbor. It's calm and quiet even in high winds. The launch service uses multiple boats so you never have to wait for more than a few minutes for a pickup. Edgartown is lovely with plenty of great restaurants and things to do. The harbormaster was kind enough to squeeze us in when we asked to move our reservation up a day, with one day's notice. The mooring (yellow 69) was at the far end of the harbor which may for a long dinghy ride, but we usually took the launch to avoid the crowded dinghy dock, and we were happy to be down away from the boating traffic.
The staff of Nantucket Moorings were helpful and responsive. As we came into the harbor, they met us and directed us to our mooring, making sure we had no difficulties picking it up and then chatting with info about the launch and other services. The harbor was full but still they were able to accommodate us coming in a day early. The only downside was that the harbor had a fair amount of chop, which is more the fault of nature and geography than the staff, but still, we did find sleeping difficult with the banging and clattering of our, and neighboring boats rocking so much.
We arrived in the late afternoon on a Friday. Was unable to get fuel as they had boats on the dock the entire time while open. Waiting for Monday morning to fuel up and they put us inline behind another larger boat and then ran out of diesel. The facilities are fine with three shower/restroom suites in a building that is heated and has a single, very slow, washer and a dryer that doesn't really dry. The mooring was fine and the harbor well protected. There is a medium amount of small boat traffic at all hours and few obey the no-wake zone and go zipping through the mooring field. We required the services of a diver while there and were thrilled with William Shepherd who came within hours of our calling and provided a wonderful review of conditions with photos and video. The marina area has little around it, but the free bus service for the entire island stops about 1/4 mile down the road. Pay attention to the schedule as you will need to get on the bus going in the right direction to avoid a round trip back to where you started for an hour. Cell service is non-existent for Verizon and weak for AT&T. There is wifi at the showers, but does not extend out to the moorings or really even the dinghy dock. The dinghy dock was crowded and the rub rail coming away, exposing nails which did a job on our dingy. Still, the staff were pleasant and helpful, the morning is safe and peaceful and the harbor quieter than others on the island, so we give it a 4 star rating.