Being one of the few, perhaps the only, trawler owner on this forum, let me offer some of my observations from five years of owning a Hatteras 48 LRC. The boat is a keeper for sure, but it is a different style of boating from a planning hull. Prior to the purchase of our 48 we owned two Hatteras planning hull boats, a 36 and 44.
Our boat is slow, but not as slow as a Nordhavn. I pass them frequently running in the ICW, when I am doing 8 knots, which is our cruising speed. I would recommend that you travel at 7 knots for a day or two and see if you like it. Trust me, that one knot is a big difference in perceived speed. A similar size sail boat will often run at 7.5 knots or better on their engine and sails. The Nordhavn may be able to cruise faster, but I have yet to see one doing it. Another opinion, do not give up twin engines. Better yet get twin engines and a bow thruster. Lots of sail area on all these style boats that can make docking in a breeze a real challenge. Be sure to go through a couple of dockings in a breeze before making a decision on any trawler. Make sure you have stabilizers or get use to rolling around with the round chines. We have all the above on our boat and it is now manageable and comfortable. Draft is also a concern as these boats draw more water than similar sized planning boats. My keel bottom is always clean down to the gel coat when I get hauled. And finally, a subjective point, there is just a big difference in going slow by choice and having no choice but to go slow.
Now for the positives and there are many. We burn 6 gallons an hour cruising at 8 knots. That includes the generator running an average light load. We carry 1400 gallons of fuel. So not only do you burn less but you get to buy fuel when you think the price is right, not every day or two out of necessity. We fuel once or twice a year with an average of about 200 engine hours each year. Raised pilothouse trawlers offer a great steering position in climate controlled accomodations, one of the best features. The piloting of the boat is relaxed as opposed to what I will rate as intense when you are on plane. The interior of the boat is much quiter when running, much less engine noise. The boats tend to be beamier than planning hulls of similar length, roomier. Smaller engines equals more room in the engine room, although fuel tanks take a lot of that extra room in our case. And, although you draw more water and will touch bottom more often, its hard to do damage to the running gear with the deep keel protection.
Hope there is some useful info in all of this to help you in the decision process.
Pete