I'm running the Bilsteins and couldn't be happier. It took a little while to find "the sweet spot" on my bike after installing them, but now even without an air gauge I know exactly where I need to set the shocks for a solo ride as well as two up when my wife's on the back.
I really fell in love with my bike all over again after riding two up however. Getting that extra weight over the back end really puts the shocks to good use. The ride over stock is unbelievable. (not that it isn't even solo riding) very plush. Very smooth, no bottoming out, I no longer frown upon the roads that used to beat me up on the stock suspension, I welcome them. All around - a very happy customer.
Post from HD Forums.