IMO, not bad rumble wise, but could be better. Very subjective though- some think this setup is too loud, while I think I could use a bit more sound. Rode with a buddy yesterday that has a 2009 Ultra Classic, all stock except for Samson slip ons, and I think his bike sounds better than mine. They are real deep and throaty. Actually, I may consider the Samsons- I was just checking out their website, and they have lots of sound clips. They also have 4" cans....I heard their quality used to suck, but I think they have improved. If they sound that good on a stock 96", they'd sound awesome on my 110" with x pipe, plus they would be different, as not many people run them.
I say that, but since our bikes exhaust exit out the rear, we don't get a good sense of what the bike sounds like from the riders seat- I should get someone to ride it and do some drive by's so that I can get a better sense of how it sounds going by.