SuperSU v2.61 BETA released
In the ongoing effort of having root on 6.0 as streamlined and seamless as possible, SuperSU v2.61 BETA was just released.
The last few BETAs have been providing SuperSU installs without touching /system, as we are modifying the boot images anyway. Since a few days ago (v2.60) the ZIP installer automagically does this boot image patching for you (for Android 6.0+, and Samsung 5.1+), significantly reducing the hassle for devices this is compatible with.
While this works great on the 6.0.x stock Nexus firmwares and even custom ROMs such as CM13, we know it still has some issues on for example the G3 and some Samsung 5.1 devices.
Keep in mind this is still a BETA, and you should only be using it if you are tech-savvy enough to fix your device if you mess it up.
In the thread below, the information in posts #2 and #3 are both relevant, with the v2.61 BETA download attached to #3. The information is still a bit scattered and sparse, a clean-up is on the to-do list :)