CrazyDave; going to get a ton of opinions & variety on this topic...best advice is to go to a bike night, or dealership & look/listen for pipes you like. Some of the top recommended are Rinehart, D&D, Vance & Hines and HD SE. I elected to go with Bub-7 true duals, but it's because I got an awesome eBay deal that was too good to pass. Best of luck w/your search...
I think it boils down to what you want. I have a 2010 Streetglide and wasn't real happy with the tame sound. But, then again, I didn't want a head pounding, can't hear for an hour after you turn it off kind of pipe either. I finally settled for the Screaming Eagle nightstick, without any modifications. Now, I can cruise at an enjoyable sound level and still hear that "Harley Sound" or I can get on it a bit and hear the rumble without the pain or nasty looks from the neighbors. I'm satisfied with the choice.