Kinect 2 and the RealSense 400 Series cameras do not use the same projection method, so it is difficult to make direct comparisons between them technologically. Kinect 2 uses 'Time of Flight' vision, whilst the D415 and D435 use Stereo imaging with left and right IR sensors. So results gained on Kinect 2 will not necessarily match images generated by the 400 Series.
You may find that you obtain a better image from the D415 model. Intel provides the following explanation for this: "Due to the wider FOV, the smaller baseline, and the smaller sensor resolution, the D435 has more depth noise (>2x) at any given range, compared to the D415. The D435 does however, benefit from having smaller minimum operation distance (minZ) at the same resolution. This means you can get closer to objects. For example, at 848x480 the D415 has a minZ of about 31cm, whereas the D435 has a minZ of about 19.5cm"
D415 also has the advantage of its RGB sensor being integrated into its camera module circuit board, whereas on the D435 the RGB sensor is attached separately.
There is an excellent guide for tuning the 400 Series cameras.
Regarding alternative cameras, the most recent advice on this matter is "We do not discuss our competitors . Feel free to google depth cameras and take a look" .