What is the best Linux OS?

By downloading each one and testing each and every one.

It is like ice cream.

Everyone loves chocolate. But dam Raspberry ripple is dam good as well. And you only know once you tried them all.

There is no such thing as "the best" Linux operating system. there are thousands of various versions of Linux all with their own strengths and weaknesses, and even some I would suggest have the same feature as both a strength and a weakness depending on user knowledge. There are very easy to set up distributions like Ubuntu or Mint, there are middle of the road distributions like Sabayon (my personal favorite) or Arch and there are distributions that allow, and encourage, full customization of the system like Slackware or Gentoo. And there are hundreds of them all in between. You can even build Linux from scratch all on your own without using a distribution (I am currently learning how to do that.) There are distributions that are aimed at doing certain things, like Backtrack which is used for security testing, there are those that are aimed at recovering your Windows operating system, there are those that are aimed at being used only over a thumb drive, there are those that are aimed at only being used on a LiveCD, and there are those that are intended to be installed to your hard drive and used as a primary OS. There is Linux aimed at cell phones, there is probably Linux being used inside that new television you just bought, among other things. That toaster in your kitchen? Yeh probably there! Ok maybe not but you get the picture. It is all over the place and is intended to be used exactly how you want it to be used. It truly is the definition of freedom in the tech world. My suggestion is to check out a few LiveCD's and see what you like. If you want to jump in right away, I would suggest learning on Ubuntu as I did, or even Mint, since on Mint EVERYTHING is set up for you right out of the box. After you are a bit more comfortable, look around at others. May I suggest Sabayon? ;) Bottom line is, there is no "best Linux" out there. If there was, there would only be that distribution, but that really is the antithesis of Linux. Linux is what you want, not what Linux wants you to have like in the Windows or Apple paradigm. Once you find "your distro" I guarantee you will want to use nothing but Linux.

It's all your opinion. This community can help choose for you based on your wants/needs though.

If you want a user friendly distro, go with Ubuntu, Linux Mint, Fedora, or Debian.

If you want a distro that's going to be really fast (like if you have a computer older than 3 years old), try distros like Lubuntu, Joli OS, Puppy, DSL, Tiny Core, or practically any distro that's running LXDE or XFCE. KDE and Gnome tends to be more resource heavy.

You would have to try and see which one fits you personally in order to know that. Not everyone will like using Fedora Red Hat, or Ubuntu (Which is my liking on it.), or Open Solaris from Oracle. It will depend on what you want to get out from using Linux there is a taste for every version. There will be some quirks in all of them. Some of them good others not so good. A long time ago when I started learning Linux in general and I had taken some courses as well at that time. I thought I was going to go Helter Skelter on Suse at that time cause I just didn't like how things were going with it. A number of years later when Ubuntu came around. I downloaded that one and used it for a little while made a switch over to Ubuntu instead. Since it suited my needs as for a Linux operating system. Sometimes you just need to get your feet wet before doing anything else. I still try a version of red hat from time to time to see what is different with them. But I still go back to ubuntu for personal reasons.

There are a great many fans I think even here in Lockergnome who have their favourite version of Linux for what ever reason it is. And most likely like me respects their decision on choosing the version they are running on their computers.

Linux Mint is the best flavor of Linux in my humble opinion.