I've recently got to create a Linux machine for some scripts testing - and I've installed Debian on my VM. After year of working on Kali and long time ago, on Ubuntu - I must say Debian itself is like a rough diamond.
I definitely advise someone just starting with Linux to leave Debian after they will feel more comfortable with some Ubuntu for example.
Well, also for more advanced freaks - there is a project called Linux From Scratch!
PS. Never completed more than couple chapters from LFS :D