Do some internet searches, theres a VERY good write up somewhere comparing exhausts, dyno testing as well.
It was one of the first places i looked when i got my first XB. D&D tested well and seems to be well liked. theres a forum member who makes a nice bit of kit as well Keda, seems like a solid guy and worth considering supporting a little guy. see his advert on the side bar on this site.
Sound is a subjective thing. what you might like others might not. the problem with all the you tube videos is also the sound quality on most recordings isnt as good as the real thing.
I have a sticker on my daily rider Sportster... "Loud Wives Lose Lives"