You know what's the best aspect of Homeworld games to me? the feeling of journey you get from going into the unknown and keeping your ships and resources from previous missions along the way. Even though Deserts of Kharak takes a big departure from the originals by having regular 2D based ground combat instead of the trademark 3D spaceship maneuvering, I still think it's a worthwhile addition to the series. The concept of land carriers is appealing to me as well.
For people who haven't played the prior entries, you get a rather slow paced RTS which is easy to get into and has a fun 10 hours or so campaign narrated by deadpan stoics. It goes very cheap during sales too.