Originally Posted by k1mu
They're different programs that do mostly the same thing. If you have SuperSU installed, there's no reason to install Superuser.
SuperSU has some additional features (like the ability to hide the su binary, and some recovery features).
I was user of Superuser with Elite combination over the ast 3 years on my Chinese pad and I can tell you it gets frustrating with Superuser becoz sometimes it doesnt gives su access and have to wait for an already approved apps sometimes even after a few retries only then it will give you back the su approval but only after you have left the application and on your homescreen.
I dont have that problem with SuperSU and now I use it with pro version never once did it reject the su request made by the apps.and changing all that on all the pads that gave me problems with superuser access has now vanish and all working well. If you look at the Superuser binaries of the version 3.3.3 it is a few hundred kb size (if not wrong 300kb) wheras SuperSU with the latest version 1.25 binaries is only less than 100kb again saves you on valuable space and lighter on the ROM.
I changed to SuperSU at the end of 2012 and never had any complains.