There is no comparison, Kinekt is the best. Cane Creek makes excellent products, I use loads of them but their seat post uses elastomers which can get hard or gummy over time and don't really do as well as a spring. The Redshift looks nice but they put all of their internals at the bottom of the post meaning you are stuck if you need to cut it down and if you want to adjust you need to remove your seat post each time. Kinekt uses springs and everything is accessible from the top making adjustments and spring replacements an absolute breeze. It may not be as sexy but functionality wise it is way better and I can cut it down as much as needed for whatever bikes. Plus it really does a great job isolating you from the bumps

I have 3 Kinekt posts on various bikes and will probably end up with more.

My only complaint is it does have a bit more setback which is to be expected but I am still able to get the saddle where it needs to be so it hasn't caused any issues so far and it is being clamped closer to where I am putting most of my pressure so not really a worry.