I had my Ds-Racer for 2 years before having to replace them, and they were still performing well.
However, I had from the start problems with blistering, which I never used to have in any other shoes.
Taping the spots before running solved that, but it's annoying having to do that before every race.
So make sure they fit your foot well, we are all different after all.
It is a very lightweight shoe, a great race companion and I know a lot of people who are very happy with it.
I used mine up to half marathons, which worked great.
I can recommend this shoe for anybody, but run around the store in them, and make sure they don't eat up your heels.
I'm 72kg and about to purchase my 3rd pair of DS Racers. I use them for races from 5k (17mins) to marathon (2:50) and have never had a problem. I train in Asics 2120's which are pretty light, but when I strap these on it's like running on air. In a marathon the balls of my forefoot heat up, but two blister plasters applied before racing solves this.