As Linux-Mag points out ([Gentoo Optimizations Benchmarked][1]) using gcc optimizations for “omg, teh speed” is not all that practical. Sure, I’ll add some compiler flags here and there as long as I am compiling everything anyway but I don’t consider that a feature of Gentoo Linux.

I actually prefer Gentoo for the package management and customization via USE flags (even with the headaches that they cause sometimes).

[1]: http://www.linux-mag.com/id/7574/