Gentoo isn't that big of a deal. I think the first time I installed it took me probably 2 hours of actual work. The last install I did took about 3 hours total, using a stage 3 tarball (that means the base system is already compiled)
It's a very nice system to have running, very maintainable.
On the other hand, if you aren't pretty familiar with the basics of a running Linux installation, the Gentoo installation process can be challenging. Fortunately there's good documentation for it.
My advice is if you want to try it as a learning experience, go for it. If you just use Linux casually and aren't a programmer and don't regularly look at source code, then maybe Gentoo will run a tiny amount faster than Debian (the *other* distro) but that's about it -- maybe not worth the hassle. Unless of course, you're in it for the journey and not the destination.
One of the cool things about the Gentoo installation procedure is that it's very flexible. I recently installed Gentoo replacing an existing Fedora installation on a dedicated server, using only SSH. That's not really something you can do with your average graphical installer. I wrote up what I did very briefly if anyone wants to read it:
http://www.mjclement.com/31/
So, yeah, a graphical installer would certainly widen the audience of Gentoo, but it's also one of the coolest things about Gentoo: you don't need any installer besides a shell.