Linux has been ready for the last twenty and I am not afraid to say it. Before moving over, I used to be the biggest Window$ fanboy you could find. I would literally preach at the smallest opportunity available and make everyone in a 10 meters radius around me groan and roll their eyeball so hard they would fall off their skull.
Then I go and buy a new laptop that I was told didn't have a pre-installed OS after paying for it. Because I had zero extra money to go and buy a copy of Window$, I ask a coworker to hook me up with something and in the time it took me to go from the store to my job, I had a SUSE Linux disk waiting for me. Back in 2005.
I unpack the laptop, we boot it to have access to the CD drive and the damn thing starts to boot into an unannounced Window$ Vi$ta. Apparently there was a Window$, unfortunately it was the wrong version, because at this point in time, for me, it was either Window$ XP or nothing. My coworker shows me how to setup up SUSE, which took all of two hours to achieve, including mannually configuring sound and graphics card. The machine is now dual booting.
Out of morbid curiosity, I play a bit on Vi$ta. It's slow, clunky, things are not where they should be. The machine burns through the battery in under 2 hours, under conservative energy settings, while under an OS I was previously completely unfamilliar with I feel more at ease, using GNOME as my desktop and the battery management is good enough that those two hours of battery life get stretched closer to three. This is roughly a 50% increase.
Remember I was this big fanboy? No M$Office, no WinAmp, no WinZip, no nothing. I'm lost. Right? Wrong. With zero effort, I get all the software I require for my daily life and then some. And it comes pre-installed. No need to rely on shady websites to get software. No hassle. No headaches. It just works.
Fast forward today.
I have zero machines in my home with Window$. I don't use it. I still know how to but I don't. I don't recommend it. I only advise using FOSS, if the person is a terminal locked-in Window$ user.
So... Linux is ready.