I'm a soon-to-be strom owner. I've been researching various crashbar options. I like the look of the Givi bars, but have also read about vibration problems. Ditto with the H&B bars. But not so much with the SW Bars. When I look at them, the reason seems to be that the overall length of bar between the mounting points is the shortest with the SW bars. The SW bars use the frontmost bolts, while the Givi and H&B bars skip over these and use the rear set of bolts.
If you think of the bars as any other vibrating object (like, say, a guitar string), then the one with the shortest length will vibrate at the highest frequency. It's the lower frequencies that people generaly notice as being annoying. Higher frequencies are less annoying. That's my theory at least, and that's why I'm going with the SW bars.
I also read a post over on VSRI where a guy filed his bars with sand, and plugged the ends with epoxy. I imagine that would help with vibration, too.