A big fan of them. These bikes are so high performance as it is no mortal human can really ride them to the limit stock so to me it doesn't really matter if I get like 5 less hp with something like a Taylor made over other exhausts I just like the way they look.
I'm glad I switched back to the undertail exhaust. I used to have a custom low mount on my 08. Too loud and it lost a ton of performance. And now with every company going back to the side mounted pipes, I'm thankful to have a different look out there.