After our 200 mile day, my female companion commented that the aftermarket seat on the Harley was more plush than the stock (but recovered) seat on the CB550. She also complained about how the passenger floorboards on the Harley are in the wrong place and that the chrome rails surrounding the hard luggage kept poking into her legs, giving her bruises after 200 miles.
She made a point of mentioning that when we hit a rough patch of road on the Harley in the desert, she felt like the whole thing was just falling apart. She said that she had never been that frightened on a motorcycle with me before. I didn't tell her, but I thought that the horrible suspension was going to pitch us into the cacti at that point too. Don't go grabbing the front brake when you need to slow down quickly, because the nose-dive will cause the front to wash out, even with the ABS.
I prefer to ride, and to tour 2-up, on the CB550 because it is a much more pleasant experience overall. Handling is better. Braking is better. Acceleration is better. Ergonomics are better. Sure the CB550 has a lot of less expensive painted (not chromed) stamped or rolled steel parts like footpegs and other brackets, but they work properly, unlike many of the pretty pieces on the Harley. Also, the stamped and rolled parts are lighter, making the CB550 lighter and therefore easier to ride. Best of all, the cheaper, lighter parts, make the CB550 much more affordable!
I'm sure somebody out there will say, "well, what if you put 1000 miles a day on it". Sorry, but realistically, I don't do 1000 mile tours very often. Chances are that not many people out there do. 100 to 200 miles days are the norm for me. Besides, after one 200 mile day on the Harley, I cannot see any genuine reason why the Harley would be better for touring. The last time I had a 500 mile day of two-up touring was several years ago, and it was just fine on my CB550.
I find that there is a great misconception that touring bikes should be heavy monsters. I don't see the benefit of a heavy motorcycle for touring. The one compelling argument I've heard was that a heavy bike might feel safer in strong sidewinds. In almost every other circumstance, a lighter, more nimble bike is superior.
One thing I have to say about the Harley is that even though many of the parts are all wrong ergonomically, they tend to be solid chunks of cast metal, and the chrome quality is good. The floorboards probably weigh 20 lbs each, and they look like chrome works of art, but they are the most uncomfortable, poorly-located, poorly-designed pieces of "art" I've ever had the misfortune to ride with.
I was meaning to ask edbikerini, if he tours 2 up on his 550. I do know people that have done this.. but if he does a lot of that, I bet his comparison to the other bike would differ..