When properly set up, a wheel on trainer tire should not slip. So the main issue is how the electronic controller responds to the game. If one is doing a race, the resistance and the timing of the resistance has to be inline with the competition. If ones trainer makes a hill slightly harder or easier than another trainer, the playing field is not the same. Not sure how we can judge this from marketing material. Everyone would need to calibrate all trainers and have data available to compare to.