As many have noted (and why I chose this place), the Cass Bay Cottages are beautiful accommodations with extraordinary views. Nothing disappointed! Everything was as described and more. Bed was comfy. Living room space was comfy and lent to a good amount of lazing around - which we needed after a week of non-stop travel. The area was peaceful.
The deck is definitely worth taking advantage of. If you're staying though a Saturday, hit up Lyttelton farmer's market to stock up on meats and veggies to grill. Then, enjoy a beautiful sunset grilling and eating while the sun goes over the mountains. There are a fair number of seasonings at the house, which was better than other accommodations we stayed at on our New Zealand trip.
It's also good to note that the sunrise can be pretty spectacular from the bedroom and deck too if you get the right mixture of clouds. We got super lucky our first morning and saw the sunrise light up the morning clouds.
Just a note, the driveway can sneak up on you. You almost don't see the sign til it's behind you. So just keep an eye out and use gps if you can.
As others noted, a car is good to have with these accommodations, since it's 20ish minutes to CBD and an easy 30-45 minute walk to Lyttelton. We also thought it was also the best to really start scratching the surface of all the great things Christchurch and Canterbury have to offer.
We loved our stay and hope to be back one day.