I went on a photo-expedition run by Photographes du Monde, a French company that specializes in tours like this. They chartered a 75-foot boat (a converted lighthouse tender) that slept up to 15 guests plus a crew of 3. We spent two weeks on the water, leaving from the tiny port of Longyearbyen (the northernmost inhabited place in the world) and cruising the coast. It was fantastic: we were in 24-hour daylight, but with the sun at a constant low angle, the lighting was nearly always ideal. It was cold, of course. Temperatures were at or just a little above freezing the entire time we were up there.
The landscapes were simply amazing as was the wildlife. We saw and photographed walruses, two species of seals, reindeer, about 20 species of birds, and a mother polar bear with twin cubs. Action was pretty much non-stop. Most of us got by with just a couple of hours of sleep per day. In two weeks I took over 6000 photos.
Conditions on the boat were cramped but surprisingly comfortable. The crew kept everything immaculate, the food was outstanding, and they really knew their business. On this trip it was important to be able to speak French, however (I do). I was the only non-native French speaker on board and all communication was in French.