I personally really love gentoo, it ignited my love for linux and my passion for tinkering.
I was afraid of trying it out because everyone keeps going on about how hard and impossible the install is supposed to be (I was not really an experienced linux user at the time).
This turned out not to be true at all, it is not a quick first install, that much is true, but reading carefully through the manual and looking up things I did not understand taught me so much more more than months of running other distros, which basically taught me nothing about linux except for the basics of using bash and a package manager.
Now I got Gentoo running on 2 machines and several VMs.
However there are things that kinda suck, as others have mentioned. One is the stubbornness and ignorance of some of the main developers or core community members.
They are a helpful bunch and their IRC guys provided me with an incredible amount of help.
But sometimes it feels as if a lot of them refuse to at least acknowledge some problems and aspects that could use some modernization.