That unit is fine, but is based on the Feedback Destroyer, but not the Pro. It is missing some features and has some that can cause you a bit of headache. Like compressor/noise gate which is not for this application. Its $30 more than the FBD so I prefer to go with a $30 used mic mixer since the FBD will end up staying in your HT equipment.

The rest can be extracted to test other speakers or used in another room for building speakers. You don't want to put your FBD out of the loop every time you want to do some speaker testing.