Just reporting that I am still using this app and every root app I use works perfectly fine with no freeze ups. Until today, I kept superuser on my phone because everything worked fine with both installed and I didnt want to mess anything up. I just got tired of seeing the superuser in the market with an update so I got around to going into root explorer and deleting the apk from system/app/ and everything still works great. After deleting it though, you need to go into SuperSU and update. If you dont get that option, you can try force closing the app and opening it again. It should prompt you to update.
Just including my experience...
SuperSU is working like a champ, but had major issues until I removed Superuser completely.
Here's how I installed:
- Install SuperSU from market
- Uninstall Superuser from settings > applications
- Launch SuperSU and allow it to update it's binary
- Delete superuser.apk from system/apps (use root explorer, es file explorer, terminal, etc...)
Since changing over to SuperSU, I haven't seen a single hang while an app is requesting su permissions.