HAL is my all time favorite cruise line (other than Home Lines years ago!) and you do see things differently somewhat. For instance, the passengers are older, are more sedate, and may have a little more money than say, Carnival passengers. HAL has much prettier flower arrangements in all of their public areas (they are noted for this) and I think most of their ships are beautiful. (Was somewhat surprised by Eurodam whose interior I thought would have been more elegant, for some reason or another, but I did not find it "up there" on par with other HAL ships. We did, however, enjoy our cruise on her.)
HAL also has a better library (which is funded by the NY TIMES so that may be the reason why it has a better and current selection of authors/books), a better culinary kitchen theater (funded by Food and Wine Magazine, ditto), and I also think their cabins are slightly more decorative and larger than other cruise ships.
I will say that their food (both MDR and PG) and on par with other lines (or maybe even worse). I think Celebrity has the best food, both in main dining room and specialty restaurants.
Having said that, I have always found HAL to go out of its way for us and whenever I have complaints, they are rectified while still on board, which I appreciate.
I have been sailing with HAL since 1981--my honeymoon cruise on the old Volendam from NYC to Bermuda and they just do that extra special something every cruise for us. That's what brings us back time and time again.
Whatever cruise line you favor, it's according to your own personal likes/dislikes, but keep in mind that not every cruise/cruise line is perfect.