Hello, i'm looking for an user-friendly Rolling Release KDE distro.
Which is the best between manjaro, chakra, sabayon... ?

Thanks!

For user friendly, Sabayon. It's well established and offers what most end users need or want.

Read the wiki first so you know what to do when it's up and running, like: Upgrading Entropy taken from Entropy and Wiki Main Page

Try with opensuse tumbleweed. Its supposed to have the latest stable software. I have got the impression many of the KDE dev use Tumbleweed at least.

If you don't mind being a little bit behind the curve (Most apps like firefox are released pretty close to the upstream release, base libraries are kept pretty stable; for KDE releases, they usually skip the first couple of minor releases, but otherwise post the updates pretty quickly), there's also PCLinuxOS. Well established, friendly community, stable, user-friendly, rolling-release, (primarily) KDE-centric.

Sabayon...

This is list of distros that ship with KDE (not all rolling) - http://kde.org/download/distributions.php.

In my opinion PClinuxOS. But it has some shortcomings.

The best is which you like the most, it's that simple . For me it is siduction which is based on Debian Sid. Very KDE, very rolling, very stable, very friendly.