Welcome to cruise-chat. The link in your post isn't working -- is this the itinerary?
Arctic Circle (Cruise)
If so, we did pretty much this same cruise in 2007 (also on Celebrity Century), only we didn't go directly to Geiranger (it was offered as an excursion out of Alesund). The trip was spectacular. Century is able to go through the fjords quite nicely. Some of the narrower ones are best traversed by smaller boats on shore excursions, though, as we did in Olden. Yet, there's a lot to see from the cruise ship. We even slept with the curtains open so as to not miss any of the passing scenery while falling asleep.
We enjoyed all of the ports (although can't comment on Geiranger), and there are differences between them. Alesund is quaint, very nice to walk around. Tromso and Molde were very nice cities with plenty to do -- nature, museums. Olden is tiny, so do a shore excursion here. This is where we had the most remarkable scenery. North Cape, out of Honingsvag, is stark -- little vegetation -- but a wonderful museum and outdoor exhibits. Bergen is a large city with an excellent fish market and outstanding views from Mount Floyen. There are sightseeing trolleys in both Bergen and Alesund.
Let us know what your interests are and we can be more specific with shore excursion options, or even the type of ship to take. As you know, there are other choices besides the mainstream cruise lines.