As usual I think that sentiment was retroactive, certainly once Vista came out. At launch, people hated the Fisher-Price look of the Luna default UI. Like, a lot. The switch to the NT based kernel for the home version of Windows also caused a shitton of people's hardware and peripherals not to work anymore because they needed new drivers and the manufacturers of said gadgets -- if they were still in business -- could not be arsed. Some of this could be alleviated by bullying that hardware's Windows 2000 drivers into working with XP. Some of it could not.
it was as stable as windows 11, but the uac system and other security chnages broke a lot of apps, including some system services. As soon as the apps adapted it became pretty decent.
About the performance, win7 isn't lighter than vista, vista just came out too early