SoftReset will soft reset (warm boot) the device using a safe method advised by msdn (microsoft developer network). There are quite a few ways to soft reset a device actually and some of them are said to be unsafe (like KernelIO method). This function will work on all Windows devices since PPC 2003 incl. WM5 and WM6
Shutdown will shut down the device using the same (HTC) method as if you’d press and hold the power on/off button for longer. On all HTC devices since the “Kaiser” the “Yes/No” dialog will be skipped and the device is shut down instantly. It will not work on non-HTC devices (will do no harm either however).
Standby will suspend the device using the same method as if you’d press and hold the power on/off button shortly. PowerOptions will exit afterwards. This function will work on all Windows devices since PPC 2003 incl. WM5 and WM6
Dim Light will turn off the backlight. PowerOptions will minimize but stay on the task list for you to switch back to full light more easily. This function will work on all HTC devices since PPC 2003 incl. WM5 and WM6- Other devices are unsure. It may or may not work (will do no harm either however).
Screen off will completely turn off the screen while WIFI, bluetooth, music etc. will still run.