Just returned from a six-night trip from Bergen to Kirkenes. While we did sail on the MS Polarlys I think my comments are germane to all of Hurtigruten's ships. The main purpose of our trip was to see the Northern Lights and we did. We saw them all three nights we were in the Arctic Circle; two nights they were pretty weak but the third night they were really nice. So that was cool!
Our cabin was very nice (we splurged on a suite) and the food was good.
On all of our previous cruises, mostly on riverboats, the highlights of the trips were the excursions. Nothing could be be further from the truth on this trip. We booked five excursions - Art Nouveau Walk in Alesund, Trondheim with Nidaros Cathedral, Lofotr Viking Feast, The Arctic Capital Tromso and the Winter Hike in Bodo - and they were all pitiful. Had they been free - and they were far from it - they would still have been a bad value. I'd strongly advise getting a map at the desk and exploring the various ports on your own; you'll see a lot more. But the excursions were not our biggest issue.