Hello Bobby,
There is no difference between sending a reset command (0x4A, ANT_ResetSystem) and using the reset pin with one minor exception: the reset pin will also reset the serial communication line. Typically you only want to use the pin reset in a situation where you serial communications have failed for some reason. Otherwise, sending a reset command should be sufficient.
Sleep and suspend are achieved entirely with the pins (there are no commands) with the exception of the "Deep Sleep" mode on the AP2 chip. There, a "Deep Sleep" mode is triggered by the SleepMessage (0xC5) command in conjunction with the SLEEP pin.
Refer to the "Power States" application note for more information on the Sleep and Suspend functions.
Best Regards,
Jefferson