I know Carnival has provided Alaska cruises for a while now so I expected them to be a bit more polished, however they fell short. They only operate in the main "mass-market" itinerary, the Seattle round-trip, with one ship. Their service offering and port calls reflect this. The Alaska scenery, wildlife, and ports are consistently great with the only variables being how rainy and cool could it be and where and when the wildlife will pop up.
First let me some of my experiences and opinions on Carnival itself and their ship the Carnival Legend:
Pre-Trip Support (GOOD):
Cabin very average. It did it's job. Not bad, not great.