The Missus and I booked a quickie on the Millennium from San Diego to Vancouver for a number of reasons.
First, there aren't that many short West Coast cruises anymore.
Second, it was an easy way to achieve Elite status on Celebrity.
Advantages: close to elevators and stairs. Easy access to cafe and pool areas. When disembarking, you're at the very top; you're the first ones on, and not likely to be bumped due to a full elevator car.
Disadvantages: long way up, if you're taking the stairs. Closeness to cafe means constant exposure to food odors. Farthest cabins away from "the action" - main dining and specialty restaurants (except Qsine), as well as lounges and entertainment. Long journey, also, from AquaSpa and fitness facility, unless you want to brave the pool deck on a cold, windy sea day.