[exspiravit]

I'm not going to argue for any particular linux distro instead of kali. Kali is essentially debian with pentesting tools installed and maybe a few other minor details. I could take a debian install abd make it kali. I'll argue that a custom hacking os is the best. 1) it's tailored to exactly your needs. 2) it's a good learning experience. 3) it can be as secure as you make it. 4) you know the ins and outs of it because heck you made it. 5) it's less susceptible to "default" attacks. Default passwords, services and apps you'd usually find on a kali install.