I would say that Kinect at least tracks more body joints than RealSense, since it can follow the leg joints. Here is a chart of Kinect's trackable joints.
RealSense can do leg tracking too, but not officially - the camera only reacts to knees, foot soles and toes because it treats them like hand palm and finger joints. You also need to remove leg wear and socks for the RealSense camera to be able to see those joints.
Kinect also had a superior operating range to an equivalent front-facing camera model such as the RealSense SR300. Kinect could track up to 4.5 m, whilst the SR300 could track up to 1.5 m. This disadvantage is no longer present in the new D415 and D435 RealSense camera models being released in the near future though, which have a substantially increased range thanks to a new vision processing chip.
In every other respect though, I would say that RealSense is the superior technology, especially for the latest new D415 and D435 cameras. You can read about these new models at the link below. The page also has a link to the full technical data sheet for the cameras.
And here is a piece I wrote about RealSense foot tracking a while ago, with an accompanying YouTube video demonstrating it.
We were also using the Kinect v2 for a product. I had previously looked at the specs and demos for the SR300, and it seemed decidedly worse in several ways (resolution, accuracy, point stability). I read about the D400 series though, and that looks like a fantastic step in the right direction. However, I had read a while back that the release date was September, then October, then nothing. This might be a bit off topic for this thread, but I can't find any information on any roadmap release date for the D400 series.
"D415 and D435 RealSense camera models being released in the near future"
Is there any information on the next predicted release date (lots of searching has yielded nothing), or is it going to be in limbo until it suddenly isn't? It's kind of hard to explain to customers that we are waiting on a camera that was supposed to be released a month ago, but was postponed to "the near future."
There is unfortunately not an updated release schedule available for the D-cameras. My understanding is that the cameras will go through a pre-order phase on the Intel Click store first.
Until then, I am encouraging RealSense users to prototype their projects with the RealSense SDK 2.0 and SR300 camera if possible so that they can easily switch to the D-cameras for enhanced range and processing capabilities once they are available to purchase.
I completely understand the frustration and project development / testing difficulties that the release delays have caused developers.