I have fitted these to replace Michelin Energy E3A as well as Energy Saver+ (I had two sets of wheels).
K425s are very comfortable tires. Their shock absorption is slightly better than both Michelins and vibration when driving has been reduced quite a bit. Rebound after passing the gap is managed really well, not like pogo stick and they settle quickly. Noise is very quiet compare to Michelins, too. I can hear them slightly however, they are similar to air noise when driving and not annoying at all. Even on rough tarmac surfaces, the noise level doesn't go up or change much, which is rather impressive. Comfort wise, I feel as if my car had a upgrade to more expensive saloon.
At low to mid speed range, initial turn in response is not as sharp as Michelins, or I could say mild, not like those more sporty tires such as BS Potenza. However, once the car starts turning with adequate roll, K425s hold very well and are stable throughout the corner. Also it is easy to keep the line I aim at than Michelins. At motorway speed, K425 are easy to keep the straight line however, I feel Michelins are slightly better. On the high speed corner, K425s are excellent, similar to at lower speed as above, and I felt confident jumping into the bends.
In the wet, I haven't had much chance to push K425 but I didn't feel any uneasiness so far. As a trial, I intentionally drove only one side of tires into large puddles on the road several times but there were no disturbance to the steering wheel, which is very different from Michelins.
Most impressive aspect of K425s is their low rolling resistance, in my case. In several occasions, when I am following the car in front with throttle off, I need to use brakes as my car keeps on going without losing the momentum than other cars in the traffic. It is evident when I am driving down hill, even if it is very slight, I could close the throttle and my car keeps on gliding. As expected, the mpg went up about 10%. This is partially because E3A has relatively high rolling resistance however, it is great news to me.
Overall, K425s are very comfortable tires and I highly recommend considering the cheaper price than those top brand tires - as the moment I don't feel any reason to pay more to by Michelin or Continentals. Its response when turning in is not as good as more sporty tires however, for family car users these are safe and comfortable option.