I had Kumho 712's. They weren't the best tire, but 4yrs ago when I bought them they where the best out there at the time for the price.I don't put on a ton of miles so I don't wear my tires out, I just look for a change after awhile.
The Kumho's had a softer sidewall, found that out right away, and would need alot of air pressure to keep them from rolling over on themselves, downside is they would slide more. The avons have really stiff sidewalls and unreal grip.
The kumho's let you know the limits and you could gather it up if they where pushed hard, but once you relized this the fun factor went away becuase they would limit you, no longer the case with the avons. I tried to push the avons hard and they kept gripping, the problem with too much grip is you need enough road on the other side of the turn to gather up the car because the tires let you go in deeper and faster, and if you finally reach the breaking point you are gonna run out of road. The point I'm trying to make is the kumhos would give up early at a lower speed than the avons, you back off the kumho's and drive out of it. That isn't really fun, and makes you not wan't too throw the car around, fearing they would loose control at some point. The avon would really need a ton of speed to break loose in a turn at which point you would need more road to catch the car. This gives me more confidents in the tire. I have no interest in pushing this tire to the limit, but I am no longer worried about having some fun spirited driving now with this tire.