The best replacement for supersu is superuser.

The best alternatives to supersu are rated as following:
★★★★★  superuser
★★  cwm superuser
★  superuser android
★  clockworkmod superuser
★  busybox
★  superuser elite
  superuser better

Your alternative for supersu is not listed? Suggest!
Speaking about supersu, one probably shouldn't forget about busybox.

Other search terms related to supersu and their ratings are:
★★★★★ busybox
★★ superuser
You have in mind a companion for supersu and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of supersu in all years. Click on graph for more.
supersu
superuser
cwm superuser