I tried Ki Pro with Sony PVE-500 and DNF 300 controller.
You can control the speed of Ki Pro but the quality of the slow is not good. There is no frame blending or another kind of frame interpolation like in a EVS or 3Play.
If you have a lot of movement in the image, you are going to see the interlace of the fields.
Depends of the use. It will not work in a set up where people expect a hi quality slow.