Bought these tires with great expectation as I heard they were quite good at a reasonable price ($800 for a set of 4). Overall, I was quite happy with the tires. They had good grip in dry conditions and really good grip in wet. They were fairly quiet and very comfortable. The 225/50R/17 (V-rated) had a nice profile and tread. The only issue I had with them was not tread wear but rather with the construction. I have a set of dedicated winter tires on separate rims that I switched over each year. Even with this, after 2-and-a-half seasons one of my i3 tires developed a sidewall bulge and had to be replaced. Just a few months later, belts snapped in two of the other tires! The resulting vibration and noise were horrendous and I ended up having to replace a front tire rod and rear bearing because of it. I'm not an overly aggressive driver and these tires should have lasted a lot longer than they did. I got less than 70% of the expected life out of them before they gave out. Because of that, I wouldn't buy them again. I switched to Yokahama tires.
I am using it for 2 years now in continental weather, from april to october. The wear is heavy, according to the markings. On dry surface the grip is moderate. On wet, it has no grip at all when You're accelerating or breaking. In the bends, it is ok if You are careful. When I bough it, I felt this was a bit weaker than I expected, but I had no serious problems with it. As for the second year it got totally unpredictable. A huge disappointment for me. Please bear in mind that the tyre size I got, is rather slim, and with wider sizes these problems might not occur.
I've used 2 sets of Continental winter and summer tyres. One set of Nokian winter tyres and now I have these Nokian i3 summer tyres. They are good for my aggressive style of driving. Today I drove these tyres at -2 celsius at snow so everything was well and smooth - no problems.