I remember finding an unmaintained Gentoo box in a corporate environment at a client's server room. It hadn't been updated for an indeterminate period of time and was running normally. However, it was a security risk so I decided to try to update it.
On Ubuntu? This would be relatively simple (this was circa 2008~2009 or so, with the box being 2 or 3 years old). On Gentoo? Impossible. Everything I tried ended up with random errors, and googling them led to more and more complexity. I just wanted to update stuff related to security, and nothing worked.
I eventually gave up and moved the app to CentOS (IIRC) and got rid of the Gentoo box. I also found RPM more irritating than APT, but much better than Gentoo.
I see a lot of pearl clutching about mainstream distros like Ubuntu and a lot of unguarded praise of distros like Gentoo, Arch or whatever. However, every single time, I remember that incident. Gentoo at home? Sure, if it works for you, do it. In a work environment? Not unless you pledge to maintain it forever.