The biggest decision to make in regard to going to Antarctica on an 'expedition' ship is how much time you wish to spend 'off the boat', and what style you want to experience while on-board.
Le Boreal is still probably the most stylish way to explore the peninsula, but because it carries 200 passengers, you will spend less time roaming about in the zodiacs than on a smaller ship with less than 100 passengers (by regulation, only 100 individuals are allowed onshore at one time).
Le Boreal does have it's failings though (as other reviewers have indicated), and when it comes up against all the other ships sailing other parts of the world, it would have some issues matching up.
Cabin 603 is one of the 3 larger ones on-board (along with the owners suite). The bathroom is awkward and small, the couch area very useful, balcony gets used very little, but being able to quickly go outside for picture taking is very helpful. And having the forward lounge right outside your cabin door (although far enough away) was great... lots of time is spent in that lounge area.