We traveled on the Kong Harald+ from Trondheim to Alesund and +Lofoten from Alesund to Bergen. We didn't specifically pick those ships--they were just the ones scheduled on the days we were traveling.
Kong Harald is a fairly modern ship, with fittings and lounges similar to cruise ships. We boarded at 10:30 AM in Trondheim and debarked at Midnight in Trondheim. We traveled as "deck passengers," which means we didn't have a cabin. It was a pleasant trip, very scenic. We did manage to get a little shut-eye in one of the lounges.
Lofoten is one of the oldest ships in the Hurtigruten line. It is a mixed passenger and cargo ship, and it's fittings are kind of elderly. We thought it had a charming retro feel to it. We boarded around 1:00 AM and debarked early in the afternoon in Bergen. Again, we were deck passengers, managing to sack out a bit in the lounge, although it got noisy when the cargo crane was in use. Once the sun came up, everyone crowded into the outside seating areas to enjoy the view.
It was an interesting adventure. I think it was the easiest way to get to and from Alesund, given our itinerary. Both ships have cafes and restaurants, which you can use for meals, on a cash (or credit card) basis.