Overall, DELL are pretty good, but I HATED my laptop (latitude 840).
IN the space of a little over a year, I had to replace the fan twice, the operating system crashed completey once due to problems with the hard drive, and recently the monitor has stopped working intermittently.
Not a big fan of DELL's customer service - when it crashed completely on a saturday morning, I called DELL tech support. Even though it was under warranty and we have a huge corporate contract with them (with "special" super-duper tech service supposedly) the assholes at DELL would not even let me talk to a tech support person until I gave them my credit card number and they charged me $30. Then when I talked to the tech, all he said was "yeah, you'll have to have your tech people reinstall the operating system - talk to them on monday" Well duh - the whole reason I called DELL was so I would be able to work, and not have to wait until Monday.
My new laptop (just got it this week) has been nothing but trouble - but I'm not sure if it's DELL fault, or the tech people at work who screwed it up.