Living here in Reno where they are located a number of the HOG Chapter members run them. I have only see one dyno print out, it was for an 06 SE Ultra, 103. The only thing done to it was the stage 1 air cleaner and the Yuill Bros Exhaust. Makes 101 hp & 100 lb ft torque at 4500 feet here in Reno.
I did a decible comparison of it with my 06 SE with same air cleaner & just SE Slip on Mufflers. Mine makes 94 hp & 101 lb ft torque at sea level. The two exhaust systems were within 1 to 2db of each other at all rpm's. The noticable difference on the MC is the lack of noise in the riding area. The rider & passenger can easily talk without yelling to each other. The rider area noise level is very low compared to my SE.
The big deal is the lack of heat, they did an incredible job of getting rid of heat. I like the system but as you say not crazy about the end cap look on the mufflers, however that is part of what makes them work.
The picture was taken more for the tour packs but shows the mufflers pretty well.