Gentoo is cargo-cult Linux. Tweaking compiler options and use flags rarely produces any measurable benefit, but it guarantees that you're using a unique, untested configuration that may expose bugs other people have never seen.

Cannot upvote this enough. Gentoo is a fools game on servers. If you want to dick around several hours every time you update your system on your desktop machine, have at it. But, if you're inviting that kind of chaos into your life on your production server that provides your livelihood, you deserve no pity (and you're unlikely to get any from anyone who has enough experience to be managing a server).

I have a vested interest in being pretty much OS agnostic; our products support tons of systems and versions, and you can easily get me to say nice things about all sorts of operating systems. But, I simply can't have no opinion about Gentoo. It's just such a poor choice for a server that I'd feel guilty not using the strongest possible language to discourage folks from using it.

Been through the horror over here, on Ubuntu now. No measurable difference in speed of the server, but plenty measurable difference in speed of deploying new ones and a major decrease in swearing from the direction of the server room.