Title is quite self-explanatory, reason I wonder is because every now and then I think to myself “maybe distro X is good, maybe I should try it at some point”, but then I think a bit more and realise it kind of doesn’t make a difference - the only thing I feel kinda matters is rolling vs non-rolling release patterns.
My guiding principles when choosing distro are that I run arch on my desktop because it’s what I’m used to (and AUR is nice to have), and Debian on servers because some people said it’s good and I the non-rolling release gives me peace of mind that I don’t have to update very often. But I could switch both of these out and I really don’t think it would make a difference at all.
NixOS is a declarative distro. Meaning it you can declare pretty much every aspect of it from what software is installed to how the system is configured from a config file.
Using your calandar example, you can list Thunderbird (or whatever) as a package you want in the configuration and it will be installed. You can also use that same configuration on another machine and produce the same environment.
Relevant to the original point, since all your software is listed in a text file, you can easily see exactly what’s installed.