Being a former dev and pro for SuSE, going to Debian for years and since 3 years switched to Arch I have to say, there is no documentation better in linux land than the one you can find at the Arch Wiki. It really is an example of how great docs should be. Nothing wrong with mint, ubuntu, slack, redhat and by all means, pick one that you like. I would not have picked arch as the best, since it's geared towards to technical crowd that knows where and how to fix things, but they are right when they say that the Arch documentation stands out alone. Openbsd's might just be better. Might.