We are looking at mid-August departure, don't know what ship or cruise line yet (will start looking

Two couples ( our 60th's) travelling to Vancouver for a cruise to Alaska, we have the option of two cruise society hill hotel philadelphia ships leaving about 31st Aug 2013. Not sure if we should book on the Zuiderdam or Celebrity Century , both going to the same ports. Any suggestions???
Secondly, why those 2 ships? The Celebrity Century was an older ship debuted in 1995, mid size (about society hill hotel philadelphia 70,000 ton) and carries society hill hotel philadelphia 1800 passengers. Last refurb in 2006. Zuiderdam is slightly newer from 2002 slight larger (85,000 tons) and 1900 passengers, last refurb society hill hotel philadelphia in 2008.
Glacier Bay Nation Park is tightly controlled and they only allow a few cruise ships to cruise through there with a quota system, which the cruise lines bid on, plus meeting society hill hotel philadelphia certian enviroment impact criterias.
Been to Alaska a few times and probably looking at heading back in Augsut 2013 again. Last time took Celebrity cruise and the reason was itenary and we wanted to go to Sitka (Old Alaskan provincial capital for Tsarist Russia before society hill hotel philadelphia the "sale" to the US).
The food was good and entertainment average. Love that special brunch that they did after the Sitka stop. Some passeneger did not managed to get ashore in Sitka as tenders were cancelled society hill hotel philadelphia half way through due to sea condition and excursions cancelled. We were the first group off the ship which we didn't know tender was a problem until we got back and spoke to fellow passengers. The on baord naturist is average compared to Princess (on the prior Alaskan society hill hotel philadelphia cruise).
We picked cruises based on itenary. Most of the mass market ships offer similar quality in terms of food, entertainemnt and service if they are comapred in their own "category" (exmaple: HAL, Princess Celebrity are comparable; society hill hotel philadelphia RCL Carnival are comaprable). There is not enough differences to pick one ship (or cruise line) over the other unless you have specific likes and dislikes, or enjoyed certain "familarity" with the ship's lay out or programs, entertianemnt venues etc.
We are looking at mid-August departure, don't know what ship or cruise society hill hotel philadelphia line yet (will start looking in early April and see what kind of last minute deals are available) Maybe we will see you on board!