And it's literally yes, yes, next, next - the defaults are pretty good.
1) Calculate Linux is 100% Gentoo with more profiles (e.g. server, desktop-kde, desktop-gnome ...etc) and after switching from vanilla Gentoo to Calculate - I didn't need to tweak any use flags of any packages.
Profiles are so good that everything works nicely together
2) There are prebuild binaries for your profile use-flag combo - can't recall last time I had to wait for something to compile
3) Much less likely to happen since you get binaries for everything - but there's additional cl-xxx tooling that makes even that easier
4) I don't think that's a bad thing. Though sure I could agree that having option to automatically restart services would be nice.
5) Yes - and you can also archive and basically have git-log on conf changes.