Exhaust looks and sound are a very personal thing. When we were doing Honda Valkyries everyone raved about the Cobra 6 into 6 pipes. They were VERY LOUD! And people were saying they added a bunch of HP.
Well, truth was they WERE very loud but they dropped between 6 and 10 hp from what the stock pipes put out. So loud does not necessarily translate into more power (though psychologically many were convinced otherwise).
I've had the stock Spyder pipe of course. Didn't like the look or the sound. Looked to me like an oversized Vespa exhaust and sounded like it too.
I saw and heard the Hindle at Daytona bike week and was underwhelmed, especially at the price. Not to knock anyone that has the Hindle. I am a firm believe that you should ride what you want. It just wasn't for me.
I decided to try the Yamaha Warrior stock pipe. It was cheap and bolted up without a problem. It was a bit louder than the stock pipe, had a much better mellow tone and I liked the look better than stock. I was very happy with that exhaust while I looked for something better.
Then we saw NMM's Micron! Awesome sound, great look and a lot louder. Can't really say it created more HP because I never dyno'd it (has anyone?). But there was no doubt the throttle response was quicker and very crisp.
But after riding it for a few thousand miles I decided the Micron was too loud for me and my Silver to Black fade paint job became Silver to Purple. I think the Spyder exit air was a bit too hot for the Micron paint.
I checked out the Tailgunner pipe that NMM sent to Lamont (where have I seen that Silver/Black Spyder before? :dontknow

. Awesome looking pipe with the turbo reverse cone and jet engine look, but it was even louder than my Micron so not the pipe for me.
Then Lamont got the Yoshimura. I was leaning towards the Carbon Fiber look anyway and the 3 sided pipe that Lamont had looked very good to me. It was quieter than either the Micron or the Tail Gunner but louder than stock and the Warrior pipe. (Do you feel a story about Goldie Locks and the 3 Bears coming on?)
Anyway, the Yoshimura pipe (for me) was
JUST RIGHT! Not too loud, and not too quiet, just the right tone while retaining the quick, crisp throttle response that I'd come to love.
My Yoshimura is the Round can where as Lamont has the 3 sided version. As far as I can tell the only real difference is in the exterior configuration (looks). I like his style better but I got a great deal on mine so I'm not complaining. Exhaust note and volume are identical between the 2 as far as I can tell.
So my rating for db levels (ear not meter) is as follows.
Stock
Hindle
Warrior
Yoshimura
Micron
Tail Gunner
According to NMM the 2 Bros pipe is REALLY LOUD! So It would probably come on at the end of this list as louder than the Tail Gunner. I haven't heard the 2 Bros so I can't say. But if that system is louder than the TG it must be close to a straight pipe.
Happy Exhaust Hunting!