Was on the Celebrity Infinity last year from/to Vancouver. It was EXCELLENT.
Ship is a little worn, especially in the cabins. But still nice, roomy facilities.
Get a balcony. Sitting out in the Inside Passage and watching the shore (a few meters away), wildlife and scenery so vastly different than the "sameness" of the Caribbean is worth the $$ for the balcony.
Itinerary was better than the Princess as it was an extra day and went to the Hubbard Glacier, much further north and "off the cruise routes" of all the other carriers.
Kechican and Juneau were good stops; Sitka isn't much.
Food was good but nothing like "the old days" as I think all of the food on Princess, Royal, Carnival and Celebrity has gone down hill in recent years.
Entertainment was good, but the sidewalks roll up at 11 pm because of the age of the cruisers!
We went Sept and had good weather and cheap!!