I didnt have many big headaches with XP. In fact, the only headache I recall having was getting some very old games working, but there were workarounds and eventually they ran fine.

Vista was only a nightmare because vista changed how drivers worked from all previous windows editions, which meant every old legacy device had to have new drivers made and signed for it, which caused major headaches for a lot of people not on the absolute latest and greatest, but that storm did eventually pass.. it should have passed in testing instead in public, which is partly why I didnt mention it, the other part being i never used it on a personal system, but Vista was ultimately a stopgap release due to delays with 7. basically a windows 6.5 if you will.