I would agree with this. I used Gentoo for a while before moving to Ubuntu.

Gentoo helps you learn and leads (forces) you down the path of getting under the hood to tweak your Linux experience.

I wouldn’t recommend it if you need to build systems quickly for production. I’m sure there are hacks to do it more quickly.

I’m really glad I used it before Ubuntu. I feel like a have a much firmer grasp of the concepts of Linux because of my experience with it.