i would say quality is good, just have to look out for common issues ..like airmatic air suspension (biggest issue), check to see if the strut tops are updated or check if airmatic has ever been worked on. crank sensors are another common failure but thats relatively cheap fix, other issues are like instrument cluster failure, cheap plastic interior parts, etc...i kno theres more..dont remember right now . if you find one thats maintained you, it should be fine. my friend has an 01 s500 with 160k miles. he had airmatic issues and crank sensor failure..not bad. im sure everyone else will chime in and add to this.! hopefully this helps