They tend to have an older population on the cruise. Quieter, more low key, lots less drunk people walking around.

If you want more of a "late night" dance club type of atmosphere, don't go to Alaska.

Alaska is easily the most scenic, and IMO had the best off shore activities as a whole. The canoeing in a glacier lake was awesome. And the opportunity to see wildlife is easily the best on an Alaskan cruise also.