This is one of the best audio products I have purchased for my Jeep. It feeds two Alpine V12 amps (4-channel and mono).
I chose this unit since it allows for sub gain AND frequency adjustment (some only have gain), in addition, the knobs are easier to adjust in a not-so-smooth-riding Jeep, little 1" sliders can be accidentally pushed up and down over bumps when trying to adjust. About PA... I have a 12+ year old Planet Audio amp in another car (Made in USA, this product is not though), and it still works great.
In an open top Jeep volume is important, adjusting the signals to your speakers allow for a higher volume before distortion versus an overall setting for all music (Rap/R&B may overwhelm the speakers before rock music would, now you can turn down the sub and lower frequencies to your speakers and turn up the volume without distortion to tailor for songs with more bass).