A lot of distro recommendation threads focus on the questions that novices think are important, but leave out the questions people would have after experiencing the differences (things that distro-hoppers might ask). As such, answers vary between "use _____, I found it very user friendly" and "use whatever, you can turn any distro into any other, and tweak it to your needs."

What are some questions that newbies should ask when deciding on which distro to use as the basis for their system. Things like "what package manager suits my needs and how do I try out different ones without changing distros?" Or "what is a desktop environment/window manager, and how do I figure out which suits me?" Or "how does an init system affect my user experience as a newbie?" Or "how what are the choices made by such-and-such distro during install?"

Bonus points for also answering the questions you propose (I don't have answers, picked a distro and stuck with it)