This PC came with 95. Went to 98, then SE, then ME. No problems. XP is a totally different animal. I've heard similar problems from Dell, Compaq (now hp also), Gateway, etc. XP is just a bigger step away from the traditional operating system.
I'll stay brand loyal. When you work for a company, you tend to buy the products with the familiar logo. I get pretty good support when I need it
I also get good discounts, and have 'given a new home' to some outdated equipment in the past.