Ubuntu is garbage. Arch is the best basically, if you can get into it. Kali is also great but highly specialized.
having said that, the simple truth is this: Linux is Linux. Distros are social constructs more than anything else. when you really get into Linux, you will learn to replace virtually any part of your Distro, which means the choice of Distro is really just a choice of "how bloated do I want my distro to be right after install?".
for that reason, arch is generally considered the best, hardest and easiest distro all in one, because the only one who can bloat your arch distro is you.
if you must have a beginner friendly distro, or simply don't feel like getting too involved with arch, you can try Manjaro which is based on arch but saves you most of the hassle.
if you don't want to go anywhere near arch, I recommend Debian, which Ubuntu is based on. However, I strongly suggest you use Gnome 2, Xfce or whatever as your window manager - just don't use Gnome 3.
Ubuntu is just a bloated Debian.