I used to build my own computers with well researched components. Always cutting edge, but windows xp (last ms os I used) did require a re instal every 6 months to a year.
5 years ago I bought a Mac pro. (had to because software I needed was Mac only). Never looked back. No problems, slowdowns, flakiness.
Mother in laws laptop is windows 7. Same garbage as xt. Don't know how ms is still in business.
What do ms servers run on? Linux. They don't even run their own software on their servers. Too flakey.
As for apple quality control, never had an issue with any of their products, from my Mac pro, iPhones, iPad, apple tv, iPods, etc.
They even exchanged my 6 year old iPod due to a defective battery.