Itinerary and ports are the same.
It is also my impression that the excursions are the same in the various ports.
Hurtigruten uses seven older and different ships - however, all have been renovated recently - please note that the cabins are very different - double beds or bunk beds. Havila's four ships are new and identical.
Both serve good Norwegian food - French delivered in the ports.
Depending on how you order, you must check the terms and conditions regarding payment and cancellation.
For Hurtigruten, there can be large differences in the raw price from the Norwegian web to 'overseas prices'