Great overview of the city.There is pre-recorded information about each stop. Due to our own time constraints, we only got off the bus at Mt. Eden which is an old volcano crater. I'd recommend it to get a higher elevation view of Auckland. Only complaint would be that for some reason the blue buses used a really offensive deodorizer that will bother anyone with allergies. The red buses didn't use this deodorizer.
I enjoyed the bus tour, but I didn't care for the city. It is loud, noisy, crowded, and a lot of hills. If you are going to use this bus, book a hotel near a stop. The hills are difficult if you are disabled or older.
Definitely stay on both routes and enjoy the sights. Very comfortable and great ac.