I think the Monza, Manta, Sprint, etc. four tip style exhaust all came about as copies of the Italian Abarth systems from the 60-70's. Everyone wanted their Fiats to have the dual-pipe-dual-tip look the V-12 Ferrari's had.
I bought a Monza many years ago. I thought the build quality was okay. But the sound was a bit too much for me. I found I would pussy-foot through my neighborhood to avoid either the open throttle blat or closed throttle burp. I used it for less than a year before going back to the stock muffler. What a relief.
I later used a Bursh quiet system for many years and thought it was okay.
I guess it's all a matter of personal taste.