Hi Entity, thanks!
I switched because I wasn't satisfied with Windows; though I don't spit on Windows, I prefer linux much much much more... Once you have switch to it you won't go back to Windows. There's so many reasons why Linux is far better for a user like me, it would be long to talk about it.
If you've never tried Linux I would warmly suggest you to give a try. You can try Linux without installing it! Just burn an iso image of a Linux distribution on a DVD (or a CD, and even an USB stick, depending of the distribution) and boot your machine on the DVD... Then if you want to install it, it's very easy, and it will realise a dual boot for you so that you can keep your Windows (then you'll have a screen during the boot where you can choose which O.S. you want to load).
I've started to use Linux in 2006, finally switch to it as my unique OS in 2008. And I've never installed Windows again (I have no Windows in any of my machines).
Ubuntu is a popular distribution easy for beginners: http://www.ubuntu.com/
The distribution I love, use, and recommend is Fedora: https://getfedora.org/
But there's many others: http://distrowatch.com/dwres.php?resource=popularity
For example there's a distribution which is made specially for reparation: https://www.system-rescue-cd.org/System ... d_Homepage