It's often said, that Gentoo is all about choice, but that doesn't quite fit what it is for me.
The highest ability to choose is Linux from scratch, after all, and I can have any amount of choice in every distribution by just going deep enough (and investing enought time).
What really distinguishes Gentoo for me is that it makes it convenient to choose.
Since we all have a limited time budget, that means, many of us only have real freedom to choose, because we use Gentoo, but that doesn't ring true in general - it misses the reason, why we can can choose. So what Gentoo gives me is not just choice, but convenient choice.
Some examples to illustrate the point:
KDE 4 without qt3
rest here