Well; I had a K-40 mag mount for a few years. Thought it was the bee's knee's UNTIL I tried a Wilson 1000 mag mount. No contest; the Wilson kicked the K-40's butt - badly.
But that is about mag-mounts; 'coily' designs are another animal.
I think the coil antenna shown above can be expected to perform similarly to other 'coily' type of antennas. They are using the same materials, the same amount of coil winds, the same diameter of the coil, etc, etc...
I think the difference between any of these designs is the details and choices in mfr process. That is; which one can handle more physical abuse and not break? IS the Predator 10k or the 55 or the Mr Coily better built than the K-40? Is K-40 building as well and selling it for less?
The difference is probably realized in the workmanship...