It is always hardest to recommend that one distro for a beginner so we start with that:
I have tested OpenSuse and it is not user friendly and stable enough for a beginner. Mageia is an option with it's Control Center and pretty stable. Mint is a very good alternative for a beginner and so is Manjaro. But I have landed on
It is Ubuntu based but has the "look changer" where you can pick "Windows 7" , "Windows XP" or "Gnome2" look with the click of a button. That is newbie friendly and will make a greenhorn - coming from Windows - feel right at home.
And that is the most important thing if you want to win someone over to Linux. Most people do not care or know what the OS is as long as it works and is easy to use.
Take Android; people don't know that it is Linux and they don't care - which is fine. It is usable and it works - that is good enough.
That is what Zorin does: you install it and you can start using it without regard to nerdy geeks who use complicated words like "terminal" and "CLI". You fire up that menu and start your Apps or install new ones via the "App store".
Zorin is not rolling so when a new version gets out you will have some hassle installing it - but by that time you will have some experience (Maybe it is time to jump to the distro recommended for the average user below?)
For the regular user there is no doubt in my mind:
OpenSuse is not flexible and reliable enough. Centos makes a fine desktop as does Debian but they are not all that flexible. Mint is a good alternative but has no rolling release. Mageia is the same and lacks on software compared to all the others mentioned here.
In this usergroup flexibility and access to pretty much any app is vital
...And that is why the winner is:
Manjaro is a rolling release so you do not have to install it more than once. It is stable and lightweight if you want it. You can have an OpenRc version without Systemd - which makes it lean and super fast - or you can have:
The package manger Pacman is the best - no need to debate that - but here is a comparison to some other package managers and for our Mageia/Mandriva using friends I have made a comparison to Urpmi
Manjaro has been rock solid and stable on my boxes for years.
For the Linux "freaks"
In this category there are four contenders:
Arch, Fedora, Slackware and Gentoo.
Fedora23 is good but has Virtualbox client issues so it is out. Slackware is the original, but I did not find it fantastic. Gentoo is...interesting and you can learn a lot. You need to compile everything and it takes a loooong time so I am way to impatient for that.
Which leaves us with the undisputed winner:
For the stability freaks and servers:
Debian Centos OpenSuse and Gentoo are the contenders and a Gentoo server might just be perfect and worth all the extra time to set it up. Centos 7 i great as is Debian and they are both pretty stable and solid. OpenSuse is not that solid.
Debian has less updates which makes it even more stable so maybe a slight upper hand for stability there. Centos is Redhat so you have the greatest and the best to back you up there. So I am not in a position to name a winner here.
So it is a tie between Debian and Centos.
Finally a review of Linux distros that is completely neutral true and indisputable .