Depends. Consumer class inspirons are not built as well as the business class Vostro's or Latitudes. I only use dell and the only serious problem i had was the video chip dying in my D620. the nVidia graphics were known to have this issue for that model. I since upgraded to a D630 and all is well again.
the business class machines are built better from the beginning and therefore tend to last much longer than the cheap, plastic inspirons found in big box stores.