The coolest distro I've found in my travels was Crunchbang Linux...hands down. It is no longer in development, but the community still carries on in it's spirit with "Bunsen Labs Linux".

It is a minimalist openbox desktop based on debian. Openbox provides a snappy and highly customizable interface with almost nothing extra included for eye-candy by default (although there is lots of room to add your own)...just sleek...mostly black and grey themed...simple.

Out of anything I've tried, it is by far the most stable experience I've had in a Linux desktop with almost everything you could possibly need working right away after install. Also, because it is openbox, there is not much in the way of gui for configuration and instead provides easy access to text configuration files through the applications menu. I learned most of what I know about Linux under the hood because this distro forced me to. And the community was fantastic for support. The Crunchbang discussion board is still up and running afaik and remains a go-to source of reliable info for me.

I'd recommend it for anyone who is ready to move on from a large and easy to use distro like Ubuntu, but is not quite ready to dive into something as intensive as Arch. I've since moved on to building up an openbox desktop from scratch on my own from a minimal Debian install, but if anyone has not had this experience, definitely give Bunsen a test drive.

Beginner? Ubuntu (any flavor) is great in that they have a solid platform and generally everything just works. It's much closer to being a drop in replacement for commercial OS's, so if you are coming from Windows or OSX, I would suggest trying that first. It's based on Debian, so of course Debian would be a reasonable choice. Fedora works well and is easy(ish) to install as well, but overall Ubuntu has had the best app support.

Advanced? Try Qubes-os, that thing is pretty amazing. Definitely not for everyone, but it's an operating system that lets you run multiple OS's at the same time with no slowdown. It comes with Fedora/Debian/Whonix and it's quite easy to run Arch etc. at the same time.

Interested in the guts? My personal fave is Gentoo, they tend to have great docs and some very smart people work on Gentoo. It's the one you use when you really want to understand how Linux works. It's not a good idea for beginners. You install and compile everything from scratch. It's an older project though, and recompiling everything all the time can be painful. That being said, you WILL learn how Linux really works.

Cool Factor? Qubes-os ;) Of course the safe answer is any version of Raspbian on Raspberry Pi, because you can make real world changes to your environment.

I think solus is a super cool OS, but it needs more work so we can migrate to it, specially when coming from ubuntu.

Elementary OS - as many distros has Ubuntu under the hoods, but provides an Apple-like UI

what a good question, :D im new on Linux, I started with Ubuntu , because i have read it a good starter and it is , i like it, but fedora seems cool too maybe im gonna change to that soon :D

Non GNU Linux distro that I find really good is Android. It uses Linux kernel is a awesome way. Good sandboxing (Android 6 and above), stable API, availability of apps etc are the features. It lags in few things like lack of open source apps, open source development model of AOSP itself etc. Hope it gets rectified in later versions.

I'm mostly an windows user but i if i need to use linux, i will try antergos

Arch for me. Tried most distros, and they all are pretty good, but I've settled on Arch. No particular reason. I just like it.

I like elementary (even if I don't use it, being as used to as I am to debian); those guys have done a pretty awesome design work and everything seems to fit quite nicely.

I really like Fedora 25 with GNOME and a good icon theme. Also ApricityOS is very good, all benefits from Arch, without the pain of installation and it looks amazing!

Personally, I love tinkering with the latest tech, I love the Port System and I love KDE. I probably also love stability, but that does not fit too well with the other stuff~ That's why, for me, Gentoo is the coolest desktop distro and StaLi for my RasPi's. Well, I guess for normal use, I prefer KaOS, which I have on my laptop.

I also tried out Suse, Kubuntu and Arch for my desktop, but I liked neither.

Hey not really a Linux distro, but i'm trying Ubuntu Budgie at the moment, and lovin'it :p coming from a macOs environment at home, i'm lovin the smooth UI and since it's Ubuntu, it rocks :)

i like arch :) personally i switch them on usecase :) i have ubuntu, centos, debian and arch running atm. i had suse as well but i'm a config guy not a gui person so yast irritated me :)