I was a hardcore Windows 7 guy. Got into system building using Windows 7 as my native OS, and then got really into the overclocking competitions, which all obviously run Windows too. I had 95% of the advanced Windows features down, and yet I made the switch and run Linux on all five of my machines now. The distro on my daily computer is Mint KDE. On my other systems it's Xubuntu, Mint Cinnamon, and Kubuntu.
Why did I switch?
#1. Linux is far faster than Windows on any platform. For basic web browsing, email, and office use, I have a repurposed Athlon 3700+ processor and 2gb of memory... it was a family member's Windows XP desktop a decade ago, before it eventually was retired due to performance limitations. It runs with almost NO LAG using Xubuntu. My dual and quad-core processors fly like nobody's business using any distro.
#2. Security! There is a myth that LInux doesn't suffer viruses because of a lack of popularity. If you look at the OS market share in the US, about 13% of computers connected to the internet run Linux. If you extrapulate the number of Windows computers infected to apply to that Linux market share, it would still be a massive number. Yet, there really isn't any self-populating "virus" in the wild. Their security model was built for networking, unlike Windows, and is much more throughtful in its design. You can still accidently install malware, but it's not going to install itself and run a muck like in Windows.
#3. Personalization. If you don't love the Windows interface, your only options are to deal until the next version is released in five years, or to go back and install an outdated version like 7 or XP and hope they keep providing security updates in a timely fashion. With Linux, there are literally more than a hundred distros to choice from, and over a dozen graphic interfaces. You can pick the one that best fits your taste, and your system specs.
There is a learning curve, and it will be somewhat frustrating, no doubt. But if you pick something user-friendly to start like Kubuntu, Xubuntu, or Mint, it won't be all that bad. And in the end, the payoff is HUGE. I will never, ever go back.