I would have to agree with this for the most part, but I'd have to add a couple things.
First off
windows XP heck, MS in general deserve a heck of a lot of credit. They have done some amazing things with their os'es in the past 2 decades. sure a little slow, but they have to cater to 80something % of the market. When a market is a couple dozen billion large, 80ish% comes out to be a rather large number of people. And to make something that most people are happy with, that's quite something.
also, the Windows os's have been pretty darn good, however, hardware manufacturers, and 3rd party software vendors, well, they kinda suck. As has been mentioned, buggy drivers suck, that's not ms's fault, thats the fault of the vendors'. i can't count how many times I've seen ATI's dll's kill my poor laptop, or open offices' program crash my desktop, or... you get the idea.
Ok, yeah mac's are better at this, but hey, I have to but new peripherals every time I buy a new mac.. AND new software... Yeah, I'll pass on the mac bus, a little too pricey for me, and apparently too pricey for the most of the rest of the world. And I haven't even started on Intel macs, no compatibility whatsoever. Most printers/Scanners/copiers... that worked on 10.4 ppc don't work on 10.4 intel mac... go figure... but that's a whole other ball game
As for linux, great os's, but as someone else rather smart has said, if they (all the companies, sorry, all the hundreds of companies making linux) would join together to make ONE good solid linux OS, it would kick @$$, untill that point in time, linux is doomed to be just a bunch of beads waiting for the string to join them together to make a beautiful necklace.