While it is true that Dell uses slightly lesser components, hardware and heatsink are so reliable nowadays that the average user rarely notices any reliability/performance differences amongst dell and more premium brands like IBM or Fujitsu.  

We have been using ~40 Dell Dimension desktops (low end) and Inpiron Laptops for almost 3 years now and the only problem we've had is one bust Maxtor hard drive.   That's not bad in my book.  Also, we received one network printer (3100cn) that didn't have a buit-in network card.  But dell sent us a replacement within 30hrs.  So they've been pretty good for us.

Slightly off topic:

Why are branded computers and accessories cheaper in the US than in China, where the products are made? anyone have any insight?