I have had great experience with dell computers.
I sat up one poweredge 1400sc for about a year ago, and it runs great, good performance, great upgradability, and best of all the price!
I have also put up around 10-15 dell dimensions (from xps r350) to 4550, and none of them have failed me yet. Even my old netplex 433 is running 24/7 (been up for over 300 days now).
The last year I have also been configuring a few inspiron notebooks, although the "feeling" to it feels el cheapo, it does work well and I havent had many problems with the 10 I configured. I had a few problems with one of them, around 10 pixels were dead. I called dell and two days later they were on my door and changed it! Even though it was sold with a 1 year CAR warranty.
Another small thing that happened for a year ago was that the mbr record became corrupted. The company I work for called dell before me, and a tech was on its way when I came out and fixed it.
(This company havent bought more than around 5-7 computers from dell within the past two years so it isn't a big customer).
Although I know several people that have had a few problems with the dell customerservice, I have had great experience. This is btw in Norway. And the support site is alot better here than in the US.