I bought a Fujitsu about a month ago and am very happy. Mine was not a desktop replacement but un ultraportable notebook (the P7010). Of course a month is not long enough to say how reliable they are from first hand experience. However, I had never owned a Fujitsu before this, so I had a similar question to yours a few weeks back.
After researching the web and posting to various forums and newsgroups, I got the feeling that Fujitsu owners were a very happy bunch and seemed to have very few complaints. The feedback I got from most people was that customer service was very good.
Search for some comments on the web. You'll find there are very few negative comments about Fujitsu notebooks.
I am loking to buy a desktop replacement notebook, and I find a Fujitsu model very attractive. Can someone tell me sometghing about the reliability of Fujitsu Lifebooks?