Weeell... I've not done the XP upgrade yet, but I'm thinking more about it now. I upgraded my brother's computer from Windows '98 to the XP Home Edtion and it's running pretty nicely. It's cool that it supports CDRW drives out of the box. I also really like the ClearType feature. It actually does make text easier and cleaner to read.
The fact that multiple users can be logged in at the same time is also impressive and I can't believe it took them this long to make that happen.
I did have a couple of glitches during the install-- a few files couldn't be found on the CD without me having to point the installer back to the "\i386" directory for some reason. Also, when I tried to "Activate Windows" (register my CD's product key as 'used' for this particular machine), it generated 8 digits less than it was supposed to for the identity key. After cancelling the activation process and running it later, it said it was already activated. So I'm not sure if it really completed or not... oh well.
The interface is different... I guess I like it, but some of the features are a little annoying and can be turned off if necessary. For the average user, I'd say XP is probably the best thing since sliced bread. Makes me wonder why they didn't call it "Windows AVG".
It did seem to migrate all of the Windows 98 settings and programs pretty well. During a subsequent program installation XP caught the installer overwriting system files with an 'unrecognized version' (older version). Fortunately, it gave me the chance to put in the XP CD-ROM and restore the proper system files.
My hope is that this will give my brother the most stable computer he's ever used. At the very least, the OS should crash less than Windows 98 did. I guess we'll wait and see.