Well i dont know about "mastering" linux. as learning to use comfortably and mastering are 2 completely different things lol
One thing you should atleast know is that linux is not an OS. linux is a kernel. the OS used with the linux kernel is GNU. so hence the name GNU/linux. (which usually gets shortened to linux)
I wouldnt suggest listening to these "hipsters" lol
popular distros such as ubuntu and mint are NOT bad. If fact they are probably the best choices for not only someone new to using linux, but also someone coming from windows.
As ubuntu/mint have the best up to date hardware support of most distros. A lot of the older and more "pure" distros of linux often have very long release cycles, and hardware support sint very good for the latest hardware.
so ya X99 launched, o well you cant use it for another 6 months, since its not supported >.>
So that one thing you can rely on something like ubuntu. aswell as supporting most all peripherals, usb devices etc.(like wireless adapters).
graphic card drivers are another one. http://support.amd.com/en-us/kb-articles/Pages/AMDCatalyst14-9LINReleaseNotes.aspx prime example.
Linux Distributions Supported:
The latest version of the ATI Catalyst™ Linux Software Suite is designed to support the following Linux distributions:
Red Hat Enterprise Linux Suite 7.0 and 6.5
SUSE® Linux Enterprise 11 SP3
OpenSUSE 13.1
Ubuntu 12.04.4 and 14.04
guess whos always on the list for things like that >.>
Also ubuntu has more of windows-like software support. Things like games are the biggest. and it usually has the best support for windows software running through WINE.
if you are wanting good help, i would direct you to here (also check out other subs linked on right side of page) http://www.reddit.com/r/linux
But for a PC gamer who wants to dabble in linux, you definitely want to use ubuntu (or a ubuntu derivative such as linux mint or something). Feel free to try any distro, and you may find one which you like better, but you will want a partition with ubuntu on it aswell, just because.
And you can always backup your home directory to span different distros. Its best and common practice to actually make your /home directory on a separate partition, and point all distros to use it, so your settings/files will always work on any distro you are running.
Just like how you do still kind of need to keep around a copy of windows, since you will always need the ability to run some windows software. linux still isnt quite there for gaming enough to replace windows as a gaming platform. And there are some commercial software (adobe being the biggest one) which you will still need windows for. (anyone who says there are free alternatives to adobe on linux has absolutely NO clue wtf they are talking about....)
You will get much more help that sub reddit then on here. As on here, its nothing but wannabe hipsters. im sure they code their own hardware drivers from scratch too lol.
O and id recommend using GNOME ubuntu rather then the standard unity ubuntu. unity is just... ehhh....
gnome is the best desktop environment imo.