I had the most problems with Windows 2000. But for shits and grins I wanted to get A+ certified and that was the current version to be tested on. Plus I was taking a Cisco course and just thought it a good idea to get the A+ cert as well. In reality don't mean much as they are good for a lifetime, and if I'd been a few months earlier I could have taken a DOS based A+ program which I would have aced without thinking about it.I was never a fan of Vista, but I never ran with any amount of regularity. There's probably some truth to there being a lot of similarities between Vista and 7, and I think a lot of the Vista problems came from running it on hardware that wasn't up to the task. But I do also think there was some refining that was done between Vista and 7 to improve the user experience. I often like to joke that Vista was the "new coke" of Windows, and that Microsoft made XP so good, that they had to release a bad version in order to release a new version that people would see as an improvement. I doubt that's actually true though, but it's a funny thought. My other nickname for Vista is the new Windows ME.
As far as my personal use I lingered long on XP, skipped Windows 8 entirely. I loved XP at the time.