Learn GNU/Linux the easy way
Let’s face it, Linux is a kernel and no matter what distribution you use, it is all the same. You have a repository of packages, you get a package manager to manage your packages, you get a desktop environment, and you get freedom to tinker down to the lowest level of the kernel to configure things like IP routing and forwarding.
Differences lie in the release cycle of the distribution, package names, and the default desktop environment – though you can find spins to even change that part. Each are trying to tackle a specific problem and come with a solution. It may be security, research, UI, stability, or even high performance computing.
If starting out, pick a user friendly distribution like Ubuntu or Debian. Use it with the defaults for 6 months while trying to learn as much as you can. Then move onto the specific use cases for Enterprise, you can use CentOS, RedHat, Ubuntu, or SUSE (you will get the best hardware/software support if you go that route) for home use, you may want to go with Debian, Ubuntu, Arch, Gentoo, Fedora or anything you want to use; for embedded, you may go with Debian, Yocto, Gentoo, OpenEmbedded, OpenWRT, and others; for stability and security, you may want to go with Debian or one of the Enterprise distributions.
At the end of the day, it is all built upon the Linux kernel – unless you are using the Debian BSD fork.