Whats better, an apple or an orange? Line up ten people and you'll get eleven answers on which is better. Since you seem to know what you are talking about, you'll have to decide.
The aft is famous for its larger balconies, less wind, less shade and the view of the wake. However, on the Voyager and Freedom class the view out the back also has a lot of structure to deal with (this is from the 8th deck on the Freedom OTS) ...
I have not been on the bump yet, but the advantages of the bump is a better view long the side and a little more privacy. A standard side view balcony is, well fairly standard. There is a little more wind, more shade and no soot (which was a problem on the Freedom - see photo) ...
Now in this case you are also comparing the Mariner (the youngest of the Voyager class) to the Freedom (newer, bigger and with a few more "things"). The Mariner will be leaving the east coast for the west coast in early 2009 if that is of any interest to you. The Freedom is bigger (too big for tendering unfortunately) and has the Flowrider (which unfortunately has limited hours) and the H2O Zone (a mini water park) which is great because the little kids can run around the H2O Zone and that leaves more room in the pool for those that want to swim.
So, you decide which is better and make that your pick.