I’ve used gentoo for a long time, it’s too easy (for me) to get OCD about per-package use flags, mixing stable/unstable versions, adding patches and doing super-minimal kernel configs.
You end up with a lot of time invested into learning and mastering a skillset that might be of no use to you outside of your own computer.
Oh, and webkit, qt, llvm, libreoffice compile times are a giant timesink.
So you might feel good about yourself when it’s all working properly, but if you have some other thing to do (like actual work on the computer), then it might get in your way.
Oh, and with most binary distributions, your backup strategy would include your files/configs and the list of packages you have installed from that distro. On gentoo, you actually need to back it all up: portage repository, compiled binaries, source code archives, header files… everything. Unless you want to recompile it all (many hours) when (not if) hardware failure occurs.
Don’t get me wrong, I really like it, I’m just not using it at the moment.
You can follow their guide to install it inside a chroot jail, you’ll get a sense of what Gentoo is without risking anything to your system, you can do that from pretty much any distro. Once the bind mounts are done and the stage3 + portage are downloaded, verified and properly unpacked (check handbook for tips), it will be happily compiling inside that chroot:
Be sure to also follow their official installation handbook, since that goes into much more detail.