I work for a consumer level computer repair company (not naming any names)
I see a lot of complaints about vista, but most of it is due to its badly implemented security. UAC is pretty useless for an everyday consumer. when your entire screen blacks out and asks you if you want to do something, most people just click yes so they can continue with what they were doing. in this way, its probably more lenient to infections.
It still gets the same infections as XP.
I have vista on my tablet, and after some fidgeting with services and background applications and doing registry tweaks (I don't recommend doing any of the above unless you know what you're doing) I can get it to boot in about 25 seconds. I have no issues with mine.
Its just the every day clueless user who are intimidated by it. I don't understand why, when it comes to technology, people's common sense just goes out the window. I would be out of a job if people had common sense and did a little bit of googling.
Vista has to be doing something right because all of American DOD is switching to Vista on endpoint stations. Probably due to the better security and the stronger domain support.
in short, what's wrong with vista? its not a unix based OS