Protect root on Android devices with stock roms

I just discovered Voodoo OTA Rootkeeper, which makes a backup copy of root (su) and could restore root after any OTA update. I guess this is useful for me since I haven't installed any custom roms on these two devices (yet) and am able to do OTA updates. The app does not work with all devices, but it works on my HTC Evo 3D phone and Asus Transformer Prime tablet.