In general, I much prefer Princess over Holland America, having cruised Princess a dozen or so times. The age group will be a bit younger on Princess, but overall, Alaska is an older cruise crowd than other cruises. Make sure that your itinerary includes Glacier Bay, as that is one of the best things to see. Personally I think you should start In Vancouver and stay as far north as possible. Starting off in Seattle, you are cruising a couple of days without seeing any of Alaska during that time. We also purposely booked our cruise going NORTH bound, as the scenery gets much more spectacular as you head north. So if you start ALL the way north, then the scenery gets LESS exciting as the cruise goes along. We also booked the land portion at the END, as the cruise portion is more relaxing and laid back, and the land portion is more active. Regardless, it's a spectacular destination. Enjoy!