I have only had one major problem since I first starting running xp, and that was it would BSOD when ever I used 3D acceleration...the nvidia loop prob. Which was due to my mobo not working well with its drivers and Geforce 3 card under xp. So I went out and got another mobo and the problem was solved.
Since then its been flawless, I do teak a bit but always backup my reg file and constantly create system restore points before loading any beta or unfamiliar programs. Other than that its been a great O/S, and I will continue to use it until something better comes along