I have a much lighter displacement boat—a 28' trimaran—and I'm using a 15kg Ronca as my primary anchor. I bought mine on the recommendation of a Kiwi friend and have been very happy with it.
One major problem I see with a lot of people is that the ground tackle on their boats is sized for fair weather only... not for the worst of what you may experience when out cruising.
I sail in Buzzards Bay and have sailed in much of New England. it is one reason I decided to go with a Rocna, rather than an older design for my primary anchor.
Given the size of your boat, you really do want to have a windlass, even a manual one like the one I just finished installing. Without it, resetting the anchor can become a nightmare, especially if it drags in the middle of the night. You can see the way I setup the new ground tackle handling system on this thread
I am always amazed at the people I see that will spend $1000 on a new GPS Chartplotter, but can't be bothered to spend the same amount of money on proper ground tackle and handling equipment. In many ways, if you are a cruiser, your safety often rests on the ability of your ground tackle to hold the boat, and your ability to recover it and reset it quickly.
One of my favorite quotes about anchors is "I generally size my anchor so that people are laughing about how big it is.. then at least I know I'm in the ballpark"
or something to that effect.
The anchorages up around here have grass, mud, and rocky bottoms for the most part. Very few are nice sandy bottoms. Block Island has grassy bottoms, the areas off of Narragansett Bay are rocky or muddy bottoms, the areas off of much of Buzzards Bay are rock, rocky or muddy bottoms. Some areas along Cape Cod are sandy, but not as many as you'd think. The areas off of Cuttyhunk Island are rocky, as are much of the coastline of Nantucket Island and Martha’s Vineyard.